What are diagnostic trouble codes and what do they mean?
The automotive industry has been developing for more than a century and it is not an easy task. Many new technologies have been invented in recent decades, such as problem diagnosis codes (DTCs). DTCs are digital instructions that indicate what is wrong with your vehicle. How can you tell if your car needs an overhaul? You can check if your car’s engine control light turns on or off, but this often doesn’t tell the whole story. If you want to learn more about why your car may need an overhaul, you’ll need to decipher the DTCs that appear in the problem diagnostic code reader (DTC) on your dashboard or, in some cases, under the hood.
The best way to understand DTCes is to learn how they work. DTCs are digital instructions used by mechanics to diagnose your car’s problems. If the engine control light comes on, you will have to find out what the cause is using the code reader. A code reader is a handheld device that reads information from the control modules inside your car. These modules control things like the engine, brakes, and others. The readings of these modules are made up of numbers and letters and give the mechanic a good idea of what is wrong.
How to find DTCs in a vehicle
The dashboard warning light is a telltale sign that something isn’t right in your car. The DTC, or Problem Diagnosis Code, lets you know what’s wrong. However, it can be difficult to find the code on your own and deciphering the readings can be confusing for even the most experienced mechanic.
I’ll show you how to find any problematic code in just 3 quick steps First, start by entering one of these two phrases into Google: “Where are my dashboard lights?”, followed by “How can I read my dashboard?” Depending on the vehicle you have, this should help you locate the dashboard lights so you know where to look for fault codes. Once there, use a pen or pencil to write everything down. If your car has a specific problem and the engine check light remains on, you will need to look up the codes and diagnose the problem.
Why These Codes May Be Important to You
Automakers indicate the specific diagnostic codes for their make and model of car. These codes can help you figure out what’s wrong with your car, but they’re not always easy to understand. However, it’s helpful to know why these codes are important to you as a driver.
Often, drivers experience health problems due to faulty oxygen sensors or catalytic converters. In some cases, airbags are known to deploy due to false temperature signals from the engine temperature sensor. In any case, knowing what DTCs mean can help you find out why your vehicle isn’t working properly so you can fix it quickly and safely.
How to Get Help With Your Car Problems
write about How to get help with your car problemsCodes If you have written down the fault codes on the dashboard, look for their meaning. Many drivers know the make and model of their car by heart.
If not, search the internet for “breakdown code” followed by the type of car you have. You can also search for “[car brand] problem code guide” Remember that there is no specific DTC list per vehicle as they are all different. Once you find out what code you have, refer to the owner’s manual to learn how to fix it. Keep in mind that most problems with your engine check light are simple fixes or easy-to-replace parts. It is important to remember that if a mechanic tells you that you need to perform a check-up immediately.
Tips to take care of your car and not need repairs so often
After all, knowing how to read dashboard codes is an important skill if you want to take care of your vehicle. Understanding what these numbers mean will help you know when it’s time for a set-up or even major repairs. If your vehicle works well, it should work wonders! Here are some tips on how to take care of your car so that it doesn’t face the constant engine light problems
Remember that regular service appointments at the dealership are the key to keeping your car running properly for years and miles. You should also keep in mind that using premium gasoline instead of regular gasoline is something that many people overlook when they are trying to save money on fuel costs. This can adversely affect your engine and cause poor performance.
Finally, it’s important to note that if a mechanic tells you that your car needs major repairs due to a problem with the engine light, they may be trying to sell you unnecessary services. If there is no immediate problem with the part indicated by the code or sensor, try to fix it yourself. For example, changing something as simple as an air filter can save a lot of money to a DIY.
DIAGNOSTIC FAULT CODES
The internet is full of stories about mysterious error messages, their meaning, and how to resolve them when they appear on the cockpit screen. The authors have received dozens of letters with questions on this topic. We are aware that there are no complete sources that offer clear answers about all possible error messages, so we decided to check if this is possible.
The aim of the book “How to diagnose?” is to give you an idea of how to solve the problems of modern cars with informational support from on-board diagnostics (OBD II, generically called OBD 2). The OBD2 Scanner has been around since 1996, but some manufacturers started using it from 1994. The standard was subsequently revised in 2000 to version 2.0; it is very similar, but with some changes that will be discussed below.
We include the most common fault codes (DTCs) recovered from cars equipped with OBD II or EOBD (European OBD). They are listed in Table 1. This table will be used to discuss the most frequently asked questions we receive on our websites and in letters.
Table 1: Error codes defined by SAE J1979 (most of them support EOBD) Error Code Number Description Probable Cause(s) Possible Solution
P0106 Engine Coolant Temperature Circuit Malfunction Engine Coolant Temperature Sensor (ECT) Circuit
P0107 Engine Coolant Temperature Circuit Range/Performance Problem in ect circuit or problem with ect itself. Check the wiring, connections and ECT sensor for proper operation.
Fix check engine light problem – is it illuminated? Does the engine malfunction when the error code appears? Are there misfires? P0108 Engine coolant temperature too high – Ignition control system performance Problem in the ECT circuit or problem with the ECT sensor itself. Check that the wiring, connections and ECT sensor are working properly.
Troubleshoot P0112 Intake Air Temperature Circuit Malfunction Intake Air Temperature Circuit (IAT)
P0113 Intake Air Temperature Circuit Range/Performance Problemin the IAT Circuit or Problem with the IAT sensor itself. Verify that the wiring, connections, and IAT sensor are working properly.
Fix Problem P0116 Engine Coolant Temperature Circuit Malfunction – Threaded Plug to the Left of the Water Pump Threaded Plug to the Left of the Water Pump Loose or Not Tight. Tighten or replace the loose plug.
P0117Motor coolant temperature circuit Range/Performance problem in the IAT circuit or problem with the IAT sensor itself. Verify that the wiring, connections, and IAT sensor are working properly.
Troubleshoot P0118 Engine Coolant Temperature Circuit – Threaded Plug on the Left Side of the Water Pump Threaded Plug on the Left Side of the Loose Water Pump ono is tight. Tighten or replace the loose plug.
P0121 Throttle Position Sensor Circuit TP Sensor Circuit Malfunction P0122 Throttle Position Sensor Circuit Range/Performance Problem in TP Sensor Circuit or Problem with TP Sensor Itself. Check that the wiring, connections, and throttle position sensors are working properly.
Troubleshoot check engine light – is the gin malfunctioning when the fault code appears? Is there a poor throttle response?
P0123 Throttle Position Sensor Circuit – Threaded plug on the left side of the water pump Loose or poorly tightened threaded plug. Tighten or replace the loose plug.
P0131 Oxygen sensor, front bench circuit #1 malfunction The O2 sensor signal of bank 1 is turned off or the O2 sensor heater circuit is open or short-circuited. Verify that the wiring, connectors, and sensors are working properly.
Troubleshoot P0132 Oxygen Sensor, Front Bench #1 Range/Performance Problem – Effect of Catalytic Converter Efficiency The O2 sensor on Bank 1 does not reach operating temperature quickly enough during engine start-up. Check engine synchronization. Automatic transmission problem? Driving problem?
P0133 Bench Front Circuit 1 The O2 sensor on Bank 1 responds slowly to the exhaust stream.
A code P0133 can also be caused by a faulty oxygen sensor heating element. Verify that the wiring, connectors, and sensors are working properly.
Troubleshoot catalytic converter P0134 Oxygen probe, front bench circuit #1 low inlet – Engine intake air system Problem in front bank O2 sensor circuit. Verify that the wiring and connectors are intact and working properly. Also check that the exhaust system is working properly
P0135 Oxygen sensor, front bench ##1 Circuit High inlet – Too rich system (Fuel adjustment system too rich) The O2 sensor of bank 1 responds to the oxygen content in the exhaust gases. Leakage in the exhaust (incorrect adjustment, loose hoses, poorly sealed joints, poorly adjusted valves), improper operation of the oxygen sensor element (inoperative heater or coherence problem).
Troubleshooting P0137 Oxygen Sensor, Rear Bench#1 Circuit Malfunction The O2 sensor signal on Bank 1 is off or the O2 sensor heater circuit is open or short-circuited. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0138 Rear Oxygen Sensor Malfunction, Bank 1 – System Too Poor (Fuel Adjustment System Too Poor) The O2 sensor on the rear bench responds to oxygen excession in the exhaust system. Exhaust leaks (improper fit, loose hoses, poorly sealed joints, poorly fitted valves), fuel injector problem, O2 sensor malfunction (inoperative heater or consistency problem).
Troubleshooting P0141 Oxygen Sensor Heater Circuit Malfunction – Bank 2 Front O2 Heater Circuit Malfunction- Bank 2 Front O2 Sensor Heating Circuit is open or short-circuited. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0142 Oxygen Sensor Circuit Malfunction – Adaptive Fuel at Start (Bank 1) The Catalyst Monitor (Bank 1) has failed to control the heating rate of the oxygen sensor during engine warm-up when starting. The monitor also does not control the heating speed of the oxygen sensor when the driver does not modulate his foot on the accelerator pedal while idling. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0143 Oxygen Sensor Circuit Malfunction – Adaptive Fuel at Startup (Bank 2) The catalyst monitor (Bank 2) haso monitors the heating rate of the oxygen sensor during engine warm-up upon start-up. The monitor also does not control the heating speed of the oxygen sensor when the driver does not modulate his foot on the accelerator pedal while idling. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0145 Oxygen Sensor Heating Circuit Mal- Bank 1 Sensor 2 The heater circuit for O2 sensor bank 1 is open or short-circuited. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0146 Bad Oxygen Sensor Heater Circuit – Bank Sensor 2 1 Bank 2 O2 Sensor Heater Circuit is open or short-circuited. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0150 Front Bank 2 Heated O2 Sensor Malfunction (Fourth Active Fuel Load) The front O2 sensor heating circuit is open or short-circuited. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0151 Front Bank 2 O2 Heating Circuit Malfunction (Second Active Refueling) Front O2 Sensor Heating Circuit is open or short-circuited. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0155 Air-fuel ratio – Sensor circuit malfunction (#1 Sensor #3) The fuel mixture in the exhaust line has been incorrectly calculated by the ECM due to a problem in the oxygen sensor heating circuit or if the heater circuit is short-circuited with the ground. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0157 Oxygen Sensor Heater Circuit Malfunction – Bank Sensor 1 3 Bank 2 O2 Sensor Heater Circuit is open or short-circuited. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0158 Oxygen Sensor Heating Circuit Malfunction – Bank Sensor 2 #1 The Front O2 Sensor Heating Circuit of Bank 2 is defective. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0159 Front O2 Error in Engine Mode #3 (Front Auxiliary) Cannot keep the loop closed during partial acceleration conditions when ordered by the ECM with the 4-Cylinder Mode 3 ThermostatThe bypass heater circuit (Bank 1) is open or short-circuited. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0160 Front O2 Error in Engine Mode #3 (Front Auxiliary) Cannot keep the circuit closed during partial acceleration conditions when ordered by the ECM with 4-cylinder mode 3 Thermostat Bypass (Bank 2) The heater circuit is open or short-circuited. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0161 Front Bank Oxygen Sensor Circuit Malfunction 1 – Adaptive Fuel at Start Faulty sensor signal detected while the catalyst monitor was monitoring the early ignition strategy. If this code appears, replace the oxygen sensor on front bank 1 so that this code disappears.
Troubleshooting P0162 Front Bank Oxygen Sensor Circuit Malfunction 1 – Catalyst Monitor Early Fuel Trimming Faulty Sensor Signal Detected While Catalyst Monitor Was Monitoring Early Ignition Strategy. If this code appears, replace the oxygen sensor on front bench 1 to clear this code.
Troubleshooting P0172 System too poor (bank 1) Poor air/fuel ratio on bench 2, measured with fully open throttle. Check fuel pressure, injectors and FPR for proper operation. Check wiring, connectors, and sensors for proper operation.
Troubleshooting P0173 System too rich (Bank 1) Bank 2 Air/fuel ratio rich measured at full throttle opening. Check the fuel pressure, injectors and FPR for proper operation. Check the wiring, connectors and sensors for correct operation.
Troubleshooting P0174 System too poor (Bank 2) Bank 1 Poor air/fuel ratio measured at full throttle opening. Check the fuel pressure, injectors and FPR for proper operation. Check the operation of cables, connectors and sensors.
Troubleshooting P0212 Barometric pressure sensor circuit malfunction Incorrect or erratic barometric pressure sensor output during testing. Check wiring, connectors and sensors for proper operation.
Troubleshooting P0213 Collector Absolute Pressure Sensor Circuit Malfunction. Incorrect or erratic output of the collector absolute pressure sensor during the test. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0222 Throttle position sensor circuit malfunction A Incorrect or erratic input of the throttle position sensor during reception of the learning or adaptation period. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0232 Throttle Position Sensor Circuit Malfunction B Incorrect or erratic input of the throttle position sensor during test reception at the upper limit. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P0233 Throttle Position Sensor Circuit Malfunction C Incorrect or erratic throttle position sensor input during test reception at the lower limit. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P1179 Fuel Rail Pressure – Too Low Incorrectly Low Fuel Rail Pressure Is Detected During Test under Closed-Loop Engine Operating Conditions. Check the fuel pressure regulator for the failure condition caused by this code. If no fault is found in the regulator, check that the fuel ducts and injectors are working properly.
Troubleshooting P1293 Detonation Sensor Circuit Malfunction – Bank 1 A faulty signal from the detonation sensor was detected while the detonation monitor monitored the engine during the closed-loop test. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P1297 Front Bank O2 Sensor Heater Circuit Malfunction 2 B An open circuit of the Front Bank Heater 2 was detected when the monitor was started. Check the wiring, connector, and sensors to see if there is a short circuit or open circuit in the heater circuits.
Troubleshooting P1310 Front Bank O2 Sensor Circuit Malfunction 2. Incorrect or erratic front bench output voltage 2 during the monitoring period. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P1321 No cam signal enPCM Incorrect or missing camshaft position sensor input detected during testing. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P1329 Crankshaft sensor signal is not detected on the PCM Incorrect or missing Crankshaft position sensor input was detected during the test. Verify that the wiring, connectors, and sensors are working properly.
Troubleshooting P1353 Tap Sensor A high or low voltage output was detected during adaptive learning or driving in closed-loop mode. Check the detonation sensor wire harness for short-circuit wires or a ground short circuit…Check the resistance of the detonation sensor module to see if there is an open condition….Check if the TOC is working properly by checking the reference signal on the E37 pin of the A8*8 bus with a voltmeter.
Troubleshooting P1355 Front Bank O2 Sensor 1 A high or low voltage output was detected during monitoring. Check the wiring, connectors, and sensors to see if they are working properly.
Troubleshooting P1357 Front Bank O2 Sensor Circuit Malfunction 2 B Front Bank Output Voltage 2 is incorrect or erratic during the monitoring period…Check the wiring, connector, and sensors for a short circuit or open circuit in the heater circuits.
Troubleshooting P1359 High Voltage on Bank Sensor 2 A High voltage in bank two sensor signals may be caused by interference from the electrical system or noise in the power supply of this circuit….Check the accessory plugs in vehicles with multiple accessories first. In vehicles using a multi-viscosity engine oil (5W30), replace the valve body and torque converter solenoid (TCS) with a new one. If code P1359 persists replace PCM Troubleshooting P1368 Idle Air Control Valve A Circuit Malfunction
The IAC valve does not work properly during the test after engine start-up. The TPS voltage was out of range when it should work properly..Check the correct operation of the IAC valve. Replace electronics if necessary… Check the ground wiring and compare with other sides during monitoring…. If the DTC is not in the history, go to the next step… Disconnect the harness from the throttle position switch (TPS) test connector. Check the resistance of the throttle position switch and compare with the specifications
Troubleshooting P1369 Idle Air Control Circuit B Malfunction
The TPSel voltage is incorrect or the IAC does not work properly during the test after the engine start….. Replace the IAC valve with a new one.
Troubleshooting P1385 Cooling Fan Relay Circuit A The fan relay circuit was open or short-circuited during the test. Test the cooling fan relay by applying the battery voltage to BATT+ and GND; next, measure the current through the cooling fan motor (the current should be less than 2.4 amps). If this doesn’t help, replace the cooling fan motor…Check the power supply between the N3/1 fuse and the F65 fuse… If the DTC is not found in the history, go to the next step… Check the pin C of the PCM connector for the ground when the key is on or the motor is running…Check AMP A fuse…
Troubleshooting P1391 Wiper High Beam Circuit
A fault was detected during the wiper high beam test. Check wiring circuits, connectors, and PCM for ground interruption
Troubleshooting P1425 EGR Valve Position Switch Circuit Malfunction The EGR Position Switch does not change state as required by the control module….Check the continuity between X17 connector terminals 1 and 4, then check the voltage to EGR at F35 terminal 2 (apply battery voltage – 3.5 V) If the DTC is not found in the history, go to the next step…Check the resistance of X17 connector terminal 1 to a good ground.
Troubleshooting P1431 Turbo Pressure Sensor A Sensor Circuit Range/Turbo A Pressure Sensor Signal is High…. Check the wiring circuits and connectors. Replace the turbocharger (if necessary). If the DTC is not found in the history, go to the next step… Disconnect the connector from the PCM wire harness. Apply 10 VDC to the plug #14 of the wire harness connector and read the voltage on the wire harness connector pin #2 on the ECM side with the on-on and motor off. NOTE: The voltage reading should be 3 to 5 volts. If it is not correct, replace the PCM.
Troubleshooting P1436 Turbo Pressure Sensor A Circuit A Under Turbo Pressure Sensor Signal A is Low….Check wiring circuits and connectors. Replace the turbocharger (if necessary).
Troubleshooting P1438 Turbo Pressure Sensor Circuit Intermittent Operating The Turbo Pressure Sensor Circuit is Intermittent. Check wiring circuits and connectors
Troubleshooting P1450 Neutral Starter Switch Circuit Malfunction
The neutral starter switch circuit was open or short-circuited during the test. Test the neutral starter switch by applying the battery voltage to NSS1 and GND, then measure the current through the neutral starter switch (the current should be less than 2.4 amps). If this does not help, replace the start switch in neutral….Check the good continuity between the terminal 86 of the X23-1 connector (neutral starter switch) and a good soil…..
Troubleshooting P1451 Reverse Inhibition Control Circuit Range/Performance
Rear gear inhibition control circuit range or performance issue…. Check the wiring circuits and connectors. Replace the reverse amenoid inhibition sun (if necessary). Check that there is good continuity between X23-1 connector terminal 85 and good soil.
Troubleshooting P1454 Low Reverse Inhibition Control Circuit
Reverse inhibition control circuit voltage problem …Check the wiring circuits and connectors. Replace the reverse inhibition solenoid (if necessary)…. Check the C-pin of the PCM connector to see if there is battery voltage when the ignition switch is ON and the motor is OFF… If there is tension, replace the PCM.
Troubleshooting P1455 Neutral Starter Switch Circuit Malfunction The Neutral Starter Switch Circuit was open or short-circuited during the test. Test the neutral starter switch by applying the battery voltage to NSS1 and GND, then measure the current through the neutral starter switch (the current should be at 2.4 amps). If this doesn’t help, replace the start switch in neutral….. Check the continuity between terminal 86 of the X23-1 connector (neutral start switch) and a good grounding…
Troubleshooting P1460 Engine Oil Temperature Sensor Circuit Malfunction Engine Oil Temperature Sensor Circuit is open or short-circuited to ground…. Check the wiring circuits and connectors. Replace the engine oil temperature sensor (if necessary)..
Troubleshooting P1461 Engine Oil Temperature Sensor Range/Performance Issue The Engine Oil Temperature Sensor Signal is outside the calibrated range. Test the engine oil temperature sensor by applying the battery voltage to terminals 1 and 3, and then measure the voltage between terminals 1 (-) and 3 (+), with the oometer. If the voltage check circuit is out of range, replace the engine oil temperature sensor. …
Troubleshooting P1462 Engine Oil Temperature Sensor Circuit with Low Voltage
The engine oil temperature sensor signal is outside the calibrated range. Test the engine oil temperature sensor by applying the battery voltage to terminals 1 and 3, then measure the voltage between terminals 1 (-) and 3 (+), with the ohmmeter. If the voltage test circuit is less than 4 volts, replace or repair the cable/circuit so that it is between 0 and 4 volts…..
And many more breakdown codes.
