engine codes
Tech Contributor
Joined: Dec 2003
Posts: 19,384
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From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Here you go, chapter and verse
I'd take a close look at those if damage is possible.
DTC P0300
System Description
The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensors and from the camshaft position (CMP) sensor in order to determine if engine misfire is occurring. By monitoring the variations in the crankshaft rotational speed for each cylinder, the PCM is able to detect individual cylinder misfire events. A misfire rate that is high enough can cause damage to the three-way catalytic converter (TWC). The malfunction indicator lamp (MIL) will flash if converter damage conditions are present.
Conditions for Running the DTC
* DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0335, P0336, P0341, P0342, P0343, P0500, P0502, P0503, P1120, P1220, P1221, or P1258 are not set.
* The engine speed is between 425-3000 RPM.
* The ignition voltage is between 10-18 volts.
* The engine coolant temperature (ECT) is between -7°C-130°C (+19°F-266°F).
* The fuel level is more than 10 percent.
* The throttle angle is steady within 1 percent.
* The anti-lock break system (ABS) and the traction control are not active.
* The transmission is not changing gears.
* The secondary air injection (AIR) diagnostic test is not in progress.
* The A/C clutch is in a steady state.
* The engine is not in fuel shut-off or in decel fuel cut-off.
* The antilock brake system (ABS) signals are not exceeding the rough road thresholds.
Conditions for Setting the DTC
* The PCM determines that an emission type misfire is present.
* The PCM determines that a catalyst-damaging misfire is present.
Action Taken When the DTC Sets
* The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.
DTC P1571
Circuit Description
The EBCM and the PCM simultaneously control the traction control. The PCM reduces the amount of torque supplied to the drive wheels by retarding spark timing and selectively turning off fuel injectors. The EBCM actively applies the brakes to the front wheels in order to reduce torque.
The EBCM sends a requested torque message via a pulse width modulated (PWM) signal to the PCM. The duty cycle of the signal is used to determine how much engine torque the EBCM is requesting the PCM to deliver. Normal values are between 10 and 90 percent duty cycle. The signal should be at 90 percent when traction control is not active and at lower values during traction control activations. The PCM supplies a pull up voltage of 5 volts that the EBCM switches to ground to create the signal.
The PCM sends a delivered torque message via a pulse width modulated (PWM) signal to the EBCM. The duty cycle of the signal is used to determine how much engine torque the PCM is delivering. Normal values are between 10 and 90 percent duty cycle. The signal should be at low values (around 10 percent) at idle and higher values under driving conditions. The EBCM supplies a pull up voltage of 12 volts that the PCM switches to ground to create the signal.
When certain PCM DTCs are set, the PCM will not be able to perform the torque reduction portion of traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P1571
One of the following conditions exists:
* The PCM detects that requested torque signal is out of the valid range.
* The PCM does not receive the requested torque signal.
Action Taken When the DTC Sets
If equipped, the following actions occur:
* The EBCM disables the TCS/VSES for the duration of the ignition cycle.
* The PCM will store conditions which were present when the DTC set as Fail Records data only.
* The Traction Control and Active Handling indicator turns ON.
* The DIC displays the following messages:
o Service Traction System
o Service Active Handling
* The ABS remains functional.
Conditions for Clearing the DTC
* The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
* The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
* The PCM automatically clears the history DTC when a current DTC is not detected in 40 consecutive warm-up cycles.
Diagnostic Aids
The following conditions can cause this concern:
* An open in the requested torque circuit
* An short to ground or voltage in the requested torque circuit
* A wiring problem, terminal corrosion, or poor connection in the requested torque circuit
* A communication frequency problem
* A communication duty cycle problem
* The PCM is not receiving information from the EBCM
* Loose or corroded EBCM ground or PCM ground
A DTC P1571 may set along with several other PCM DTCs if the key is held in the CRANK position while the engine is running. The starter lockout function of the PCM is enabled several seconds after the engine is running and prevents the starter from engaging while the engine is running. This will cause a partial loss of power to some components and systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
3.
Clear the DTC in order to verify that the fault is present.
4.
Measure the requested torque signal in order to determine if the signal has a valid duty cycle.
5.
Measure the requested torque signal in order to determine if the signal has a valid frequency.
11.
This vehicle is equipped with a PCM which uses an electrically erasable programmable read only memory (EEPROM). When replacing the PCM, the replacement PCM must be programmed.
I'd take a close look at those if damage is possible.
DTC P0300
System Description
The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensors and from the camshaft position (CMP) sensor in order to determine if engine misfire is occurring. By monitoring the variations in the crankshaft rotational speed for each cylinder, the PCM is able to detect individual cylinder misfire events. A misfire rate that is high enough can cause damage to the three-way catalytic converter (TWC). The malfunction indicator lamp (MIL) will flash if converter damage conditions are present.
Conditions for Running the DTC
* DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0335, P0336, P0341, P0342, P0343, P0500, P0502, P0503, P1120, P1220, P1221, or P1258 are not set.
* The engine speed is between 425-3000 RPM.
* The ignition voltage is between 10-18 volts.
* The engine coolant temperature (ECT) is between -7°C-130°C (+19°F-266°F).
* The fuel level is more than 10 percent.
* The throttle angle is steady within 1 percent.
* The anti-lock break system (ABS) and the traction control are not active.
* The transmission is not changing gears.
* The secondary air injection (AIR) diagnostic test is not in progress.
* The A/C clutch is in a steady state.
* The engine is not in fuel shut-off or in decel fuel cut-off.
* The antilock brake system (ABS) signals are not exceeding the rough road thresholds.
Conditions for Setting the DTC
* The PCM determines that an emission type misfire is present.
* The PCM determines that a catalyst-damaging misfire is present.
Action Taken When the DTC Sets
* The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.
DTC P1571
Circuit Description
The EBCM and the PCM simultaneously control the traction control. The PCM reduces the amount of torque supplied to the drive wheels by retarding spark timing and selectively turning off fuel injectors. The EBCM actively applies the brakes to the front wheels in order to reduce torque.
The EBCM sends a requested torque message via a pulse width modulated (PWM) signal to the PCM. The duty cycle of the signal is used to determine how much engine torque the EBCM is requesting the PCM to deliver. Normal values are between 10 and 90 percent duty cycle. The signal should be at 90 percent when traction control is not active and at lower values during traction control activations. The PCM supplies a pull up voltage of 5 volts that the EBCM switches to ground to create the signal.
The PCM sends a delivered torque message via a pulse width modulated (PWM) signal to the EBCM. The duty cycle of the signal is used to determine how much engine torque the PCM is delivering. Normal values are between 10 and 90 percent duty cycle. The signal should be at low values (around 10 percent) at idle and higher values under driving conditions. The EBCM supplies a pull up voltage of 12 volts that the PCM switches to ground to create the signal.
When certain PCM DTCs are set, the PCM will not be able to perform the torque reduction portion of traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P1571
One of the following conditions exists:
* The PCM detects that requested torque signal is out of the valid range.
* The PCM does not receive the requested torque signal.
Action Taken When the DTC Sets
If equipped, the following actions occur:
* The EBCM disables the TCS/VSES for the duration of the ignition cycle.
* The PCM will store conditions which were present when the DTC set as Fail Records data only.
* The Traction Control and Active Handling indicator turns ON.
* The DIC displays the following messages:
o Service Traction System
o Service Active Handling
* The ABS remains functional.
Conditions for Clearing the DTC
* The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
* The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
* The PCM automatically clears the history DTC when a current DTC is not detected in 40 consecutive warm-up cycles.
Diagnostic Aids
The following conditions can cause this concern:
* An open in the requested torque circuit
* An short to ground or voltage in the requested torque circuit
* A wiring problem, terminal corrosion, or poor connection in the requested torque circuit
* A communication frequency problem
* A communication duty cycle problem
* The PCM is not receiving information from the EBCM
* Loose or corroded EBCM ground or PCM ground
A DTC P1571 may set along with several other PCM DTCs if the key is held in the CRANK position while the engine is running. The starter lockout function of the PCM is enabled several seconds after the engine is running and prevents the starter from engaging while the engine is running. This will cause a partial loss of power to some components and systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
3.
Clear the DTC in order to verify that the fault is present.
4.
Measure the requested torque signal in order to determine if the signal has a valid duty cycle.
5.
Measure the requested torque signal in order to determine if the signal has a valid frequency.
11.
This vehicle is equipped with a PCM which uses an electrically erasable programmable read only memory (EEPROM). When replacing the PCM, the replacement PCM must be programmed.
Last edited by DeeGee; Jul 17, 2009 at 12:59 AM.
