Pinpoint Test S: DTC P27B4

Normal Operation and Fault Conditions

The resolver speed sensor monitors the speed and direction of the resolver. If the resolver turns in a reverse direction when D is selected or in a forward direction when R is selected, the SOBDMC sets a DTC.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
SOBDMC P27B4:00	Internal Control Module Transmission Gear Direction Control Performance: No Sub Type Information	This DTC indicates the resolver speed sensor detects the resolver rotating in a reverse direction when D is selected or a forward direction when R is selected.

Possible Sources

Module not programmed with most current software
Rear electric drive assembly

S1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Using the diagnostic scan tool, clear all diagnostic trouble codes.

Ignition OFF.

Wait 10 seconds.

Road test the vehicle.

In a parking lot, shift the vehicle between P, D and R, allowing the vehicle to move in both directions.

In a parking lot, engage the active park assist feature, and shift out of N.

Using the diagnostic scan tool, carry out the SOBDMC continuous memory self-test.

Is DTC P27B4 present?

Yes

GO to S2

No	The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

S2 RETRIEVE ALL CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (DTCS) FROM ALL MODULES
- Ignition ON.
- Using the diagnostic scan tool, retrieve all continuous memory diagnostic trouble codes (DTCs).
Are any other diagnostic trouble codes (DTCs) present?

Yes RESOLVE those DTCs first. REFER to the Master DTC Chart.

No GO to S3

S3 IDENTIFY VEHICLE SYMPTOMS
- Using the diagnostic scan tool, clear all diagnostic trouble codes.
- Ignition OFF.
- Wait 10 seconds.
- Road test the vehicle.
- In a parking lot, shift the vehicle between P, D and R, allowing the vehicle to move in both directions.
- In a parking lot, engage the active park assist feature, and shift out of N.
Is an observable symptom present?

Yes DIAGNOSE and REPAIR all vehicle symptoms first.

No GO to S4

S4 PROGRAM THE SOBDMC (SECONDARY ON-BOARD DIAGNOSTIC CONTROL MODULE C) WITH THE LATEST CALIBRATION
- Using the diagnostic scan tool, program the SOBDMC with the latest calibration. REFER to: Module Programming .
- Road test the vehicle.
- In a parking lot, shift the vehicle between P, D and R, allowing the vehicle to move in both directions.
- In a parking lot, engage the active park assist feature, and shift out of N.
- Using the diagnostic scan tool, carry out the SOBDMC continuous memory self-test.
Is DTC P27B4 present?

Yes GO to S5

No The concern is not present at this time. It may have been caused by a corrupted calibration.

S5 BLANK PATH PROGRAM THE SOBDMC (SECONDARY ON-BOARD DIAGNOSTIC CONTROL MODULE C) WITH THE LATEST CALIBRATION
- Using the diagnostic scan tool, blank path program the SOBDMC with the latest calibration. REFER to: Module Programming .
- Road test the vehicle.
- In a parking lot, shift the vehicle between P, D and R, allowing the vehicle to move in both directions.
- In a parking lot, engage the active park assist feature, and shift out of N.
- Using the diagnostic scan tool, carry out the SOBDMC continuous memory self-test.
Is DTC P27B4 present?

Yes INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

No The concern is not present at this time. It may have been caused by a corrupted calibration.