Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B138A 03: Device Voltage Reference Group 1 Outputs Voltage Below ThresholdDTC B138A 07: Device Voltage Reference Group 1 Outputs Voltage Above Threshold
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
8-Volt Reference | B0954 06, B0955 06, B0956 06, B0957 06, B0958 06, B0959 06, B0960 06, B0961 06, B138A 03 | B0954 06, B0955 06, B0956 06, B0957 06, B0958 06, B0959 06, B0960 06, B0961 06, B138A 03 | B138A 07 | -- |
Left Front Corner Object Sensor Signal | B0954 06 | B0954 06 | B0954 01 | B0954 08, B0954 21 |
Left Front Middle Object Sensor Signal | B0955 06 | B0955 06 | B0955 01 | B0955 08, B0955 21 |
Right Front Middle Object Sensor Signal | B0956 06 | B0956 06 | B0956 01 | B0956 08, B0956 21 |
Right Front Corner Object Sensor Signal | B0957 06 | B0957 06 | B0957 01 | B0957 08, B0957 21 |
Left Front Corner Object Sensor Signal | B0954 06 | B0954 06 | B0954 01 | B0954 08, B0954 21 |
Left Front Middle Object Sensor Signal | B0955 06 | B0955 06 | B0955 01 | B0955 08, B0955 21 |
Right Front Middle Object Sensor Signal | B0956 06 | B0956 06 | B0956 01 | B0956 08, B0956 21 |
Right Front Corner Object Sensor Signal | B0957 06 | B0957 06 | B0957 01 | B0957 08, B0957 21 |
Left Rear Corner Object Sensor Signal | B0958 06 | B0958 06 | B0958 01 | B0958 08, B0958 21 |
Left Rear Middle Object Sensor Signal | B0959 06 | B0959 06 | B0959 01 | B0959 08, B0959 21 |
Right Rear Middle Object Sensor Signal | B0960 06 | B0960 06 | B0960 01 | B0960 08, B0960 21 |
Right Rear Corner Object Sensor Signal | B0961 06 | B0961 06 | B0961 01 | B0960 08, B0960 21 |
Low Reference | -- | B0954 06, B0955 06, B0956 06, B0957 06, B0958 06, B0959 06, B0960 06, B0961 06 | -- | -- |
Circuit/System Description
The object sensors are 3-wire sensors that are used to determine the distance between the vehicle and an object of interest. The object alarm module supplies an 8 V reference and ground reference to each of the object sensors. The object alarm module triggers the sensors in a sequential loop. After each sensor transmits, the object alarm module uses the sensor ring received through the signal circuit to calculate the distance and position of an object.
Conditions for Running the DTC
| • | DTC B1325 is not set |
| • | The vehicle is in REVERSE or DRIVE |
Conditions for Setting the DTC
B138A 03
The object alarm module detects the sensor 8 V reference circuit is less than 7.2 V.
B138A 07
The object alarm module detects the sensor 8 V reference circuit is greater than 9.2 V.
Action Taken When the DTC Sets
| • | Parking assist system is disabled. |
| • | SERVICE PARK ASSIST message is displayed in the driver information center and a chime will sound. |
Conditions for Clearing
| • | The object alarm module clears the history DTC when a current DTC is not detected in 100 ignition cycles. |
| • | The condition for the DTC is no longer present. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Object Detection Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, transmission in REVERSE, verify that the scan tool Sensor Supply Voltage parameter is between 7.2 - 9.2 V.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at each of the object sensors.
- Ignition ON, verify DTC B138A is not set as current.
- Install each sensor harness connector one at a time, checking DTCs after each sensor is connected. Verify DTC B138A is not set as current.
| ⇒ | If the DTC is set, test the 8 V reference circuit terminal 1 for a short to voltage, short to ground, or an open/high resistance. If circuit tests normal, replace the object alarm module. |
| ⇒ | If the DTC is set, replace the object sensor that was connected immediately before the DTC set. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for object alarm module replacement, setup, and programming. |
