DTC B1000 35: ECU ROM Data Integrity
DTC B1000 36: ECU EEPROM Data Integrity
An internal fault is detected inside the controller. External circuits are not affected.
The controller executes an internal fault detection routine upon receiving a power-on command. The only necessary condition is the presence of supply voltage and ground. This program is executed even if the voltage is outside the allowed operating range.
An internal fault has been detected in the controller.
The controller disables all auxiliary inputs.
- The current fault code is cleared after the fault disappears.
- The DTC is cleared from the log when the ignition cycle counter in the controller reaches the reset threshold of 50 without recurring the fault.
- This DTC can be stored in the DTC log without affecting the functionality of the controller.
- If the DTC is only logged and not issued as a current DTC, do not replace the controller.
- If a DTC is received as both current and logged, replace the controller that generated the DTC.
If this DTC is received as current, replace the controller that generated this DTC.
Perform a post-repair diagnostic check after completing 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 can generate this DTC.
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 persists for at least 5 seconds.
DTC B1325 07
- The controller detects that the system voltage is above a calibrated value, typically 18V.
- The above condition persists for at least 5 seconds.
- The controller immediately disables all outputs when an out-of-voltage voltage is detected, except for GMLAN and relays "Work/Start", which turn off after a 3-minute delay.
- The issuance of other fault codes is blocked.
- The current fault code is cleared after the fault disappears.
- The DTC is cleared from the log when the ignition cycle counter in the controller reaches the reset threshold of 50 without recurring the fault.
| Step | Operation | Values | Yes | No |
| 1 |
Has the vehicle system diagnostic check been completed?
|
-
|
Go to Step 2
|
Check the vehicle with a diagnostic tool.
|
| 2 |
Is the displayed value of the parameter "battery voltage" within the specified range?
|
9 - 18 V
|
Go to Step 3
|
Go to Step 4
|
| 3 |
DTC issued as current?
|
-
|
Go to Step 7
|
|
| 4 |
Is the measured value within the specified range?
|
9 - 18 V
|
Go to Step 6
|
Go to Step 5
|
| 5 |
Check the battery positive voltage circuit for the following:
Has the cause been found and fixed?
|
-
|
Go to Step 9
|
|
| 6 |
Test all controller ground circuits for an open or high resistance.
Has the cause been found and fixed?
|
-
|
Go to Step 9
|
Go to Step 7
|
| 7 |
Inspect the harness connector on the controller under test for loose connections. Go to Section 9A, "Checking body wiring systems for intermittent faults and contact problems".
Has the cause been found and fixed?
|
-
|
Go to Step 9
|
Go to Step 8
|
| 8 |
Replace defective controller. See replacement, setup, and programming procedures in section Controller Reference.
Has the replacement been completed?
|
-
|
Go to Step 9
|
-
|
| 9 |
Operate the system to check if the problem has been fixed.
Has the cause been found and fixed?
|
-
|
System OK
|
Go to Step 2
|
DTC B3078 01: Safety System Output Circuit Short to Ground
DTC B3078 06: Safety System Output Circuit Short to Battery or Open
Auxiliary Body Controller (XBCM) operates the horn relay by grounding the control circuit of the horn relay coil to energize the relay.
The ignition switch is set to the ON position.
The left turn signals must be on and the signal to turn on the left turn signal must be given.
The XBCM detects an open, short to ground, or short to voltage on the security horn circuit by applying voltage to the circuit.
The security horn does not sound.
- The conditions for issuing this DTC are no longer valid.
- The fault code is removed from the log after 100 ignition cycles without a fault.
- The BCM is commanded to clear the code from the scan tool.
- Circuit Check
- Connector repair
- Check for Intermittent Faults and Bad Contacts
- Wiring repair
Ignition ON, scan tool enable left rear turn signal output control on the auxiliary body controller (XBCM). The turn signal relay command parameter in the data list should show "INCLUDED", and the left rear turn signal should be on.
- Test the horn relay control circuit for an open or short to battery voltage.
- Inspect the harness connector at the XBCM controller for loose connections.
- If all circuits and connections are normal, replace the XBCM.
Perform a post-repair diagnostic check after completing the diagnostic procedure.
Controller information for replacing, configuring and programming XBCM. See Section 9V, "body controller".
DTC B3887 02: Trailer Left Turn Signal Circuit Short to Ground
DTC B3887 05: Trailer Left Turn Signal Circuit Short to Battery or Open
Before performing the diagnostic procedure, perform a Diagnostic System Check on the vehicle. See Section 9A, "Checking body wiring systems for intermittent faults and contact problems".
When the left turn signal switch is in the ON position, ground is connected to the auxiliary body controller (XBCM) through the turn signal switch circuit. The XBCM then applies voltage to 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 the signal to turn on the left turn signal must be given.
The BCM detects an open, short to ground, or short to voltage on the left rear turn signal circuit by applying voltage to that circuit.
The left rear turn signal does not light up.
- The conditions for issuing this DTC are no longer valid.
- The fault code is removed from the log after 100 ignition cycles without a fault.
- The BCM is commanded to clear the code from the scan tool.
- Circuit Check
- Connector repair
- Check for Intermittent Faults and Bad 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 bulb for an open or shorted filament.
- If the lamp is defective, replace the lamp.
- Turn off the turn signal switch, clear the DTC, test the left rear turn signal circuit for a short to voltage, short to ground, open, or high resistance.
- If all circuits and connections are normal, replace the XBCM.
Perform a post-repair diagnostic check after completing the diagnostic procedure.
Controller information for replacing, configuring and programming 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 the diagnostic procedure, perform a Diagnostic System Check on the vehicle. See Section 9A, "Checking body wiring systems for intermittent faults and contact problems".
When the right turn signal switch is in the ON position, ground is connected to the auxiliary body controller (XBCM) through the turn signal switch circuit. The XBCM then applies voltage to 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 on the right rear turn signal circuit by applying voltage to that circuit.
The right rear turn signal does not light up.
- The conditions for issuing this DTC are no longer valid.
- The fault code is removed from the log after 100 ignition cycles without a fault.
- The BCM is commanded to clear the code from the scan tool.
- Circuit Check
- Connector repair
- Check for Intermittent Faults and Bad 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 an open or shorted filament.
- If the lamp is defective, replace the lamp.
- Turn off the turn signal switch, clear the DTC, test the left rear turn signal circuit for a short to voltage, short to ground, open, or high resistance.
- If all circuits and connections are normal, replace the XBCM.
Perform a post-repair diagnostic check after completing the diagnostic procedure.
Controller information for replacing, configuring and programming XBCM.
DTC B3891 02: Trailer Fog Lamp Circuit Short to Ground
DTC B3891 05: Trailer Fog Lamp Circuit Short to Battery or Open
Before performing the diagnostic procedure, perform a Diagnostic System Check on the vehicle. See Section 9A, "Checking body wiring systems for intermittent faults and contact problems".
When the rear fog light switch is in the ON position, ground is connected to the auxiliary body controller (XBCM) through the rear fog light switch circuit. The XBCM then energizes the rear fog light circuit.
The ignition switch is set to the ON position.
Parking lights must be on, a command must be given to turn on the rear fog lights.
The BCM detects an open, short to ground, or short to voltage in the rear fog light circuit by applying voltage to the circuit.
The rear fog lights do not light up.
- The conditions for issuing this DTC are no longer valid.
- The fault code is removed from the log after 100 ignition cycles without a fault.
- The BCM is commanded to clear the code from the scan tool.
- Circuit Check
- Connector repair
- Check for Intermittent Faults and Bad Contacts
- Wiring repair
Ignition ON, scan tool enable Rear Fog Light Output Control on the Auxiliary Body Controller (XBCM). The rear fog light relay command parameter in the data list should show "INCLUDED", and the rear fog lights should be on.
- Inspect the rear fog light bulb for an open or shorted filament.
- If the lamp is defective, replace the lamp.
- Turn off parking lights, clear DTC, test rear fog light circuit for short to voltage, short to ground, open or high resistance.
- If all circuits and connections are normal, replace the XBCM.
Perform a post-repair diagnostic check after completing the diagnostic procedure.
Controller information for replacing, configuring and programming XBCM.
Controllers connected to the high and low speed GMLAN serial links monitor serial communications during normal vehicle operation. Between the controllers there is an exchange of operational information and commands. The controllers have pre-recorded information about what messages should 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 sending controller. Each message contains the identification number of the transmitting controller.
body controller (BCM) activates the serial line enable and auxiliary wake-up circuits for the serial line by applying voltage when the ignition switch is in the ACC, ON, or START position.
The voltage in the system is 9 - 16 V.
Serial communication is required for the vehicle power mode master to operate.
A monitored regular message indicating the availability of the transmitting controller was not received.
The controllers have never signaled, so certain subsystems will not work.
The current fault code is cleared after the fault disappears.
The DTC is cleared from the log when the ignition cycle counter in the controller reaches the reset threshold of 50 without recurring the fault.
Turn off parking lights, clear DTC, test rear fog light circuit for short to voltage, short to ground, open or high resistance.
If there are multiple non-communicating modules, select the one closest to the DLC slot.
Some modules may not have internal protection for some of the outputs, which may cause the battery positive voltage fuse or the ignition voltage fuse to blow. If the input voltage fuse is blown but no short circuit is detected on this circuit, verify that the controllers do not have a voltage output circuit shorted to ground before replacing the controller.
This diagnostic can be applied to any controller that needs to communicate over a high or low speed GMLAN serial link, provided the vehicle is equipped with the option that uses this controller.
Perform a post-repair diagnostic check after completing the diagnostic procedure. See Section 9A, "Body Wiring Systems".
Controllers connected to the high and low speed GMLAN serial links monitor serial communications during normal vehicle operation. Between the controllers there is an exchange of operational information and commands. The controllers have pre-recorded information about what messages should 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 sending controller. Each message contains the identification number of the transmitting controller.
body controller (BCM) activates the serial line enable and auxiliary wake-up circuits for the serial line by applying voltage when the ignition switch is in the ACC, ON, or START position. Serial link enable circuit wakes up brake controller (EBCM) for bus communication, and an auxiliary serial line wake-up circuit wakes up the motor controller (ECM) and gearbox controller (TCM).
- The system supply voltage is in the range of 9-16 V
- The vehicle power mode master requires a working serial link.
A monitored regular message indicating the availability of the transmitting controller was not received.
The controllers have never signaled, so certain subsystems will not work.
- The current fault code is cleared after the fault disappears.
- The DTC is cleared from the log when the ignition cycle counter in the controller reaches the reset threshold of 50 without recurring the fault.
If there are multiple non-communicating modules, select the one closest to the DLC slot.
Some modules may not have internal protection for some of the outputs, which may cause the battery positive voltage fuse or ignition voltage fuse to blow. If the input voltage fuse is blown but no short circuit is detected on this circuit, verify that the controllers do not have a voltage output circuit shorted to ground before replacing the controller.
This diagnostic can be applied to any controller that needs to communicate on a high or low speed CAN serial link, provided the vehicle is equipped with the option that uses this controller.
This diagnostic can be applied to any controller that needs to communicate over a high or low speed GMLAN serial link, provided the vehicle is equipped with the option that uses this controller.
Using the troubleshooting tips above, determine which controller is having a communication problem and what needs to be checked.
Ignition OFF, disconnect the harness connector at the controller that is not communicating.
Important: Only high speed CAN controllers have a serial line enable circuit OR an auxiliary serial line wakeup circuit. If the offending controller is missing one of these circuits, go to step 4.
Ignition ON, verify the test lamp illuminates between the serial link enable circuit OR the serial link auxiliary wakeup circuit and ground.
If the test lamp does not illuminate, repair the open or high resistance in the circuit. If there are no open circuits, replace the BCM.
Ignition ON, test for a test lamp illuminated between all of the battery positive voltage circuits and ground.
If the test lamp does not illuminate, repair 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 failed controller.
Test for a test lamp illuminated between all ignition voltage circuits and ground.
If the test lamp does not illuminate, repair 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 failed controller.
Verify that the resistance between the controller ground circuits and ground is less than 1 ohm.
If it is greater than 1 ohm, repair the open in the ground circuit.
Determine if the controller with communication failure is using a low speed CAN serial link.
If the controller only uses high speed GMLAN, replace the controller.
Verify that the resistance on the low speed CAN serial link circuit between the offending controller and the controller issuing the DTC is less than 1 ohm.
If resistance is greater than 1 ohm, test the low speed CAN serial link for an open or high resistance.
If all circuits are OK, replace the controller with the communication problem.
Perform a post-repair diagnostic check after completing the diagnostic procedure. See Section 9A, "Body Wiring Systems". Replacing, configuring and programming the associated controller and the controller with communication failure.