Pinpoint Test Aa: DTC P27B1, P27B2, P27B3
WARNING: This page is about a different variant/trim than selected.
- Normal Operation and Fault Conditions
The TCM monitors transmission performance to make sure it always operates in a safe manner. If a safety violation is detected, a DTC will set, and the TCM will attempt to mitigate the concern by disabling actuators in the transmission. If the TCM is not able to achieve a safe operating state, all actuators in the transmission will be disabled. To clear P27B1, P27B2, P27B3 from the TCM, a power down of the module is required.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition TCM P27B1:00 Internal Control Module Transmission Range Select Performance: No Sub Type Information The TCM sets this DTC if the safety software detects a fault related to the clutch shafts. TCM P27B2:00 Internal Control Module Transmission Range Control Performance: No Sub Type Information The TCM sets this DTC if the safety software detects a fault related to the parking lock system. TCM P27B3:00 Internal Control Module Transmission Gear Select Performance: No Sub Type Information The TCM sets this DTC if the safety software detects a fault related to one of the CAN buses. Possible Sources
- Transmission internal fault
- TCM fault
- AA1 CHECK THE TCM (TRANSMISSION CONTROL MODULE) FOR DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, carry out the TCM self-test.
Are any other diagnostic trouble codes (DTCs) present in the TCM?
Yes RESOLVE those diagnostic trouble codes (DTCs) first. REFER to the Diagnostic Trouble Code (DTC) Chart . No GO to AA2 - AA2 CHECK THE TRANSMISSION FOR PROPER OPERATION
- Ignition OFF.
- Refer to TRANSMISSION CONTROLS - TR9070 for schematic and connector information. REMOVE BJB fuse 19 (VBATT to TCM) to initiate TCM power down.
- WAIT 1 minute for TCM to completely power down.
- INSTALL BJB fuse 19.
- Ignition ON.
- Using a diagnostic scan tool, clear all diagnostic trouble codes (DTCs) from the TCM.
- In a safe location, shift the transmission between drive, reverse and park, letting the vehicle move in both directions.
- Road test the vehicle, paying attention for transmission performance related symptoms.
- Using a diagnostic scan tool, carry out the TCM self-test.
Are any observable symptoms present?
Yes If any other diagnostic trouble codes (DTCs) are now present in the TCM, resolve those first. REFER to the Diagnostic Trouble Code (DTC) Chart . Otherwise, REFER to: Diagnosis By Symptom No If no symptoms or diagnostic trouble codes (DTCs) other than P27B1, P27B2 and/or P27B3 are present, INSTALL a new TCM. REFER to: Transmission Control Module (TCM)