Contents: Diagnostic Trouble Code (DTC) B1000 ↧ ECU controller malfunction ↧ Diagnostic Trouble Code (DTC) B1325 ↧ Device power supply circuit failure ↧ Diagnostic Trouble Code (DTC) B3078 ↧ Security System Horn Output Circuit ↧ Diagnostic Trouble Code (DTC) B3887 ↧ Left rear turn signal circuit ↧ Diagnostic Trouble Code (DTC) B3888 ↧ Right rear turn signal circuit ↧ Diagnostic Trouble Code (DTC) B3891 ↧ Rear fog light circuit ↧ Diagnostic Trouble Code (DTC) B0140 ↧ Communication failure with body… ↧ Diagnostic Trouble Code (DTC) U0155 ↧ Communication failure with the… ↧
DTC B1000 35: ECU ROM Data Integrity
DTC B1000 36: ECU EEPROM Data Integrity
Internal fault detection is performed inside the controller. External circuits are not affected.
The controller executes a program to detect an internal fault when it receives a power-on command. The only requirement is that the supply voltage and ground are present. This program is executed even if the voltage is outside the permissible operating range.
An internal fault has been detected in the controller.
The controller disables all additional inputs.
- The current fault code is cleared once the fault has disappeared.
- The fault code is cleared from the history when the ignition cycle counter in the controller reaches the reset threshold of 50 without the fault recurring.
- This DTC may be stored in the DTC history without affecting the operation of the controller.
- If the fault code is only stored in the log and is not issued as a current fault code, the controller should not be replaced.
- If the DTC is received both as a current DTC and as a stored DTC, replace the controller that generated the DTC.
If this DTC is received as current, replace the controller that set this DTC.
Perform a post-repair diagnostic check upon completion of the diagnostic procedure.
Controller information for replacing, configuring and programming the BCM. See Section 9V, "Body Controller".
DTC B1325 03: Voltage Below Threshold
DTC B1325 07: Voltage Above Threshold
The controllers on this vehicle monitor battery voltage through the battery positive voltage circuits. There are many controllers on the vehicle that could set this trouble code.
The voltage supplied to the controllers is in the range of 7-26 V.
DTC B1325 03
- The controller detects that the system voltage is below a calibrated value, typically 9V.
- The above condition is maintained for at least 5 seconds.
DTC B1325 07
- The controller detects that the system voltage is higher than a calibrated value, typically 18 V.
- The above condition is maintained for at least 5 seconds.
- The controller immediately turns off all outputs when a voltage out of tolerance is detected, except for GMLAN and the Run/Start relay, which turn off after a 3-minute delay.
- The generation of other fault codes is blocked.
- The current fault code is cleared once the fault has disappeared.
- The fault code is cleared from the history when the ignition cycle counter in the controller reaches the reset threshold of 50 without the fault recurring.
| Step | Operation | Values | Yes | No |
| 1 |
Has the vehicle system diagnostic check been completed?
|
-
|
Proceed to Step 2
|
Check the vehicle with a diagnostic tool.
|
| 2 |
Is the displayed value of the "battery voltage" parameter within the specified range?
|
9 - 18 V
|
Proceed to Step 3
|
Proceed to Step 4
|
| 3 |
Is the fault code issued as current?
|
-
|
Proceed to Step 7
|
|
| 4 |
Is the measured value within the specified range?
|
9 - 18 V
|
Proceed to Step 6
|
Proceed to Step 5
|
| 5 |
Check the battery positive voltage circuit for the following defects:
Has the cause been found and corrected?
|
-
|
Proceed to Step 9
|
|
| 6 |
Check all controller ground circuits for opens or high resistance.
Has the cause been found and corrected?
|
-
|
Proceed to Step 9
|
Proceed to Step 7
|
| 7 |
Inspect the harness connector on the controller being tested for contact problems. Go to Section 9A, "Checking Body Wiring Systems for Intermittent Malfunctions and Contact Failures."
Has the cause been found and corrected?
|
-
|
Proceed to Step 9
|
Proceed to Step 8
|
| 8 |
Replace the faulty controller. See the replacement, setup and programming procedures in the section Controller Reference Materials.
Is the replacement complete?
|
-
|
Proceed to Step 9
|
-
|
| 9 |
Operate the system to check if the problem has been corrected.
Has the cause been found and corrected?
|
-
|
The system is normal
|
Proceed to Step 2
|
DTC B3078 01: Security System Output Circuit Short to Ground
DTC B3078 06: Security System Output Circuit Short to Battery or Open
The auxiliary body control module (XBCM) controls the horn relay by grounding the horn relay coil control circuit to energize the relay.
The ignition switch is set to the ON position.
The left turn signals must be on and a signal must be given to turn on the left turn signal.
The XBCM controller detects an open, short to ground, or short to voltage in the security system horn circuit and applies voltage to the circuit.
The security system alarm does not sound.
- The conditions for issuing this DTC are no longer valid.
- The fault code is cleared from the history after 100 ignition cycles without a fault.
- The BCM receives a command to clear the code from the scan tool.
- Checking the chain
- Repair of connectors
- Checking for intermittent faults and poor contacts
- Wiring repair
Turn the ignition on, use a scan tool to activate the left rear turn signal output control at the additional body control module (XBCM). The Turn Signal Relay Command parameter in the data list should show "ON" and the left rear turn signal should illuminate.
- Check the horn relay control circuit for an open or short to battery voltage.
- Inspect the wiring harness connector on the XBCM controller for poor connections.
- If there are no faults in all circuits and connections, replace the XBCM.
Perform a post-repair diagnostic check upon completion of the diagnostic procedure.
Controller information for replacing, configuring and programming the XBCM. See Section 9V, "Body Controller".
DTC B3887 02: Trailer Left Turn Signal Circuit Short to Ground
DTC B3887 05: Left Trailer Turn Signal Circuit Short to Battery or Open
Before performing a diagnostic procedure, perform a vehicle system diagnostic check. See Section 9A, "Checking the body wiring systems for intermittent faults and contact problems."
When the left turn signal switch is turned to the ON position, ground is connected to the auxiliary body control module (XBCM) through the turn signal switch circuit. The XBCM then supplies voltage through the rear turn signal circuit to the left rear turn signal.
The ignition switch is set to the ON position.
The left turn signals must be on and a signal must be given to turn on the left turn signal.
The BCM detects an open, short to ground, or short to voltage in the left rear turn signal circuit and applies voltage to the circuit.
The left rear turn signal does not light.
- The conditions for issuing this DTC are no longer valid.
- The fault code is cleared from the history after 100 ignition cycles without a fault.
- The BCM receives a command to clear the code from the scan tool.
- Checking the chain
- Repair of connectors
- Checking for intermittent faults and poor contacts
- Wiring repair
Turn on the ignition, turn on the left rear turn signal switch, the left rear turn signal should light up.
- Inspect the left rear turn signal lamp for a broken or shorted filament.
- If the lamp is faulty, replace the lamp.
- Turn off the turn signal switch, clear the DTC, check the left rear turn signal circuit for a short to voltage, short to ground, open or high resistance.
- If there are no faults in all circuits and connections, replace the XBCM.
Perform a post-repair diagnostic check upon completion of the diagnostic procedure.
Controller information for replacement, setup and programming of XBCM.
DTC B3888 02: Trailer Right Turn Signal Circuit Short to Ground
DTC B3888 05: Trailer Right Turn Signal Circuit Short to Battery or Open
Before performing a diagnostic procedure, perform a vehicle system diagnostic check. See Section 9A, "Checking the body wiring systems for intermittent faults and contact problems."
When the right turn signal switch is turned to the ON position, ground is connected to the auxiliary body control module (XBCM) through the turn signal switch circuit. The XBCM then supplies voltage through the rear turn signal circuit to the right rear turn signal.
The ignition switch is set to the ON position.
The right turn signals must be on and a signal must be given to turn on the right turn signal.
The BCM detects an open, short to ground, or short to voltage in the right rear turn signal circuit and applies voltage to the circuit.
The right rear turn signal does not light.
- The conditions for issuing this DTC are no longer valid.
- The fault code is cleared from the history after 100 ignition cycles without a fault.
- The BCM receives a command to clear the code from the scan tool.
- Checking the chain
- Repair of connectors
- Checking for intermittent faults and poor contacts
- Wiring repair
Turn on the ignition, turn on the right rear turn signal switch, the right rear turn signal should light up.
- Inspect the right rear turn signal bulb for a broken or shorted filament.
- If the lamp is faulty, replace the lamp.
- Turn off the turn signal switch, clear the DTC, check the left rear turn signal circuit for a short to voltage, short to ground, open or high resistance.
- If there are no faults in all circuits and connections, replace the XBCM.
Perform a post-repair diagnostic check upon completion of the diagnostic procedure.
Controller information for replacement, setup and programming of XBCM.
DTC B3891 02: Trailer Fog Light Circuit Short to Ground
DTC B3891 05: Trailer Fog Lamp Circuit Short to Battery or Open
Before performing a diagnostic procedure, perform a vehicle system diagnostic check. See Section 9A, "Checking the body wiring systems for intermittent faults and contact problems."
When the rear fog lamp switch is turned to the ON position, ground is connected to the auxiliary body control module (XBCM) through the rear fog lamp switch circuit. The XBCM then supplies voltage to the rear fog lamp circuit.
The ignition switch is set to the ON position.
The parking lights must be on and the command to turn on the rear fog lights must be given.
The BCM detects an open, short to ground, or short to voltage in the rear fog lamp circuit and applies voltage to the circuit.
The rear fog lights do not work.
- The conditions for issuing this DTC are no longer valid.
- The fault code is cleared from the history after 100 ignition cycles without a fault.
- The BCM receives a command to clear the code from the scan tool.
- Checking the chain
- Repair of connectors
- Checking for intermittent faults and poor contacts
- Wiring repair
Turn the ignition on, activate the rear fog lamp output control at the additional body control module (XBCM) using a scan tool. The rear fog lamp relay command parameter in the data list should read "ON" and the rear fog lamps should illuminate.
- Inspect the rear fog light bulb for a broken or shorted filament.
- If the lamp is faulty, replace the lamp.
- Turn off the parking lights, clear the fault code, check the rear fog light circuit for a short to voltage, short to ground, open or high resistance.
- If there are no faults in all circuits and connections, replace the XBCM.
Perform a post-repair diagnostic check upon completion of the diagnostic procedure.
Controller information for replacement, setup and programming of XBCM.
The controllers connected to the high-speed and low-speed GMLAN serial links monitor the serial link communications during normal vehicle system operation. Operational information and commands are exchanged between the controllers. The controllers have pre-recorded information about what messages are to be exchanged over the serial links in each virtual network. These messages are monitored, and in addition, certain regular messages are used by the receiving controller to determine the availability of the transmitting controller. Each message contains the identification number of the transmitting controller.
The body control module (BCM) activates the serial communication enable circuit and the auxiliary serial communication wake-up circuit by applying voltage when the ignition switch is in the ACC, ON, or START position.
The voltage in the system is 9 - 16 V.
The vehicle power mode master device requires serial data exchange to operate.
A controlled regular message determining the availability of the transmitting controller was not received.
The controllers never issued signals, so certain subsystems will not work.
The current fault code is cleared once the fault has disappeared.
The fault code is cleared from the history when the ignition cycle counter in the controller reaches the reset threshold of 50 without the fault recurring.
Turn off the parking lights, clear the fault code, check the rear fog light circuit for a short to voltage, short to ground, open or high resistance.
If there are multiple modules that do not support communication, select the one closest to the DLC connector.
Some modules may not have internal protection for some outputs, which can cause the battery positive voltage fuse or ignition voltage source fuse to blow. If the input voltage fuse has blown, but no short circuit is detected in that circuit, make sure that there are no shorted to ground voltage output circuits on the controllers before replacing the controller.
This diagnostic can be used on any module that is required to communicate over the high or low speed GMLAN serial data line, provided the vehicle is equipped with an option that uses that module.
Perform a post-repair diagnostic check after completing the diagnostic procedure. See Section 9A, "Body Wiring Systems".
The controllers connected to the high-speed and low-speed GMLAN serial links monitor the serial link communications during normal vehicle system operation. Operational information and commands are exchanged between the controllers. The controllers have pre-recorded information about what messages are to be exchanged over the serial links in each virtual network. These messages are monitored, and in addition, certain regular messages are used by the receiving controller to determine the availability of the transmitting controller. Each message contains the identification number of the transmitting controller.
The body control module (BCM) activates the serial communication enable circuit and the auxiliary serial communication wake-up circuit by applying voltage when the ignition switch is in the ACC, ON, or START position. The serial communication enable circuit wakes the electronic brake control module (EBCM) for bus communication, and the auxiliary serial communication wake-up circuit wakes the engine control module (ECM) and transmission control module (TCM).
- The system supply voltage is in the range of 9-16 V
- A functioning serial data link is required for the vehicle power mode master to operate.
A controlled regular message determining the availability of the transmitting controller was not received.
The controllers never issued signals, so certain subsystems will not work.
- The current fault code is cleared once the fault has disappeared.
- The fault code is cleared from the history when the ignition cycle counter in the controller reaches the reset threshold of 50 without the fault recurring.
If there are multiple modules that do not support communication, select the one closest to the DLC connector.
Some modules may not have internal protection for some outputs, which can cause the battery positive voltage fuse or ignition voltage source fuse to blow. If the input voltage fuse has blown, but no short circuit is detected in that circuit, make sure that there are no shorted to ground voltage output circuits on the controllers before replacing the controller.
This diagnostic can be applied to any controller that must communicate over a high or low speed CAN serial link, provided the vehicle is equipped with an option that uses that controller.
This diagnostic can be used on any module that is required to communicate over the high or low speed GMLAN serial data line, provided the vehicle is equipped with an option that uses that module.
Using the diagnostic recommendations above, determine which controller has a communication problem and what needs to be checked.
Turn off the ignition, disconnect the wiring harness connector on the controller where the connection is broken.
Important: Only high-speed CAN controllers have a serial link enable circuit OR an auxiliary serial link wake-up circuit. If the controller with the communication problem does not have one of these circuits, go to step 4.
Turn ignition ON, verify that the test lamp illuminates between the serial data line enable circuit OR the auxiliary serial data line wake-up circuit and ground.
If the test lamp does not light, repair the open or high resistance in the circuit. If there are no faults in the circuits, replace the BCM.
Turn on the ignition, check if the test lamp lights between all positive battery voltage circuits and ground.
If the test lamp does not light, eliminate the short to ground or open/high resistance in the circuit. If the circuit fuse is blown, also check the positive voltage outputs on the controller for a short to ground. If the circuits are OK, replace the faulty controller.
Check if the test lamp lights between all ignition voltage circuits and ground.
If the test lamp does not light, eliminate the short to ground or open/high resistance in the circuit. If the circuit fuse is blown, also check the positive voltage outputs on the controller for a short to ground. If the circuits are OK, replace the faulty controller.
Check that the resistance between the controller ground circuits and the ground is no higher than 1 Ohm.
If it is higher than 1 Ohm, repair the open circuit in the ground circuit.
Determine if the controller with the communication problem is using a low speed CAN serial communication line.
If the controller uses only high speed GMLAN communication line, replace the controller.
Check that the resistance in the low-speed CAN serial communication line between the controller with the communication problem and the controller generating the fault code is not higher than 1 ohm.
If the resistance is greater than 1 ohm, check the low speed CAN serial communication line for an open or high resistance.
If all circuits are OK, replace the controller with communication problems.
Perform a post-repair diagnostic check after completing the diagnostic procedure. See Section 9A, "Body Wiring Systems". Replacement, adjustment and programming of the linked controller and the controller with communication failure.
The article was borrowed from the website chevyman.ru