Pinpoint Test Ai: DTC P27B2, P27B3, P27B4, P27B5, P27B6
- Normal Operation and Fault Conditions
The PCM monitors the TSS, OSS, ISSA and ISSB sensors to verify the achieved gear matches the selected gear. If the PCM detects a reverse gear when a forward gear is selected, a forward gear when reverse is selected, an incorrect gear ratio or a mismatch between speed sensors, it will set a DTC.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P27B2:00 Internal Control Module Transmission Range Control Performance: No Sub Type Information This DTC indicates a mismatch between the commanded gear range and the achieved gear range while entering or exiting park. PCM P27B3:00 Internal Control Module Transmission Gear Select Performance: No Sub Type Information This DTC indicates an incorrect gear state. PCM P27B4:00 Internal Control Module Transmission Gear Direction Control Performance: No Sub Type Information This DTC indicates the PCM detected a reverse engagement when a forward gear was selected, or a forward engagement when reverse was selected. PCM P27B5:00 Internal Control Module Transmission Gear Ratio Control Performance: No Sub Type Information This DTC indicates a mismatch between the speed sensor readings and the commanded gear ratio. PCM P27B6:00 Internal Control Module Transmission Speed Sensor Performance: No Sub Type Information This DTC indicates a mismatch between the TSS, ISSA and ISSB sensors. Possible Sources
- Clutch fault
- Speed sensor fault
- TR sensor fault
- GSM fault
- PCM
- AI1 CHECK FOR GSM (GEAR SHIFT MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, retrieve all diagnostic trouble codes (DTCs) from the GSM.
Are any GSM diagnostic trouble codes (DTCs) present?
Yes RESOLVE GSM diagnostic trouble codes (DTCs) first. REFER to: External Controls . No GO to AI2 - AI2 CHECK FOR PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, clear all diagnostic trouble codes (DTCs) from the PCM.
- Road test the vehicle.
- In a parking lot, shift the vehicle between Park, Drive and Reverse, allowing the vehicle to move in both directions.
- Using a diagnostic scan tool, carry out the PCM self-test.
Is DTC P27B2, P27B3, P27B4, P27B5 and/or P27B6 present in the PCM?
Yes GO to AI3 No The fault is not present at this time. If any observable symptoms are present, REFER to: Diagnosis By Symptom . - AI3 RETRIEVE ALL DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE PCM (POWERTRAIN CONTROL MODULE) SELF-TEST
- Ignition ON.
- Using a diagnostic scan tool, retrieve all diagnostic trouble codes (DTCs) from the PCM self-test.
Are any shift solenoid, speed sensor, TR sensor, clutch engagement or module communication diagnostic trouble codes (DTCs) present?
Yes RESOLVE any shift solenoid, speed sensor, TR sensor or clutch engagement diagnostic trouble codes (DTCs) first. REFER to the DTC Chart RESOLVE any module communication diagnostic trouble codes (DTCs) second. REFER to Diagnostic Trouble Code (DTC) Chart . No If any gear engagement symptoms are present, RESOLVE those first. REFER to: Diagnosis By Symptom . If only P27B2, P27B3, P27B4, P27B5 and/or P27B6 are present with no symptoms, GO to AI4 - AI4 PROGRAM THE PCM (POWERTRAIN CONTROL MODULE) WITH THE LATEST CALIBRATION
- Using a diagnostic scan tool, clear all diagnostic trouble codes (DTCs) from the PCM.
- Program the PCM with the latest calibration. REFER to: Module Programming .
- Carry out the transmission strategy download. REFER to: Transmission Strategy Download .
- Road test the vehicle.
- In a parking lot, shift the vehicle between Park, Drive and Reverse, allowing the vehicle to move in both directions.
- Using a diagnostic scan tool, carry out the PCM self-test.
Is DTC P27B2, P27B3, P27B4, P27B5 and/or P27B6 present in the PCM?
Yes Refer to PCM GUIDED ROUTINE TESTING
After programming the new PCM, carry out the transmission strategy download. REFER to: Transmission Strategy Download .No The concern is not present at this time. It may have been caused by a corrupted calibration.