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 Descriptor
DTC B138A 03: Control Module Voltage Reference Output Circuit Low VoltageDTC B138A 07: Control Module Voltage Reference Output Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
8 V Reference | B0958 06, B0959 06, B0960 06, B0961 06, -- B138A 03 | B0958 06, B0959 06, B0960 06, B0961 06, | B0958 06, B0959 06, B0960 06, B0961 06, -- B138A 07 | -- |
Left Rear Object Sensor Signal | B0958 06 | B0958 06 | B0958 01 | B0958 08, B0958 21 |
Left Middle Rear Object Sensor Signal | B0959 06 | B0959 06 | B0959 01 | B0959 08, B0959 21 |
Right Middle Rear Object Sensor Signal | B0960 06 | B0960 06 | B0960 01 | B0960 08, B0960 21 |
Right Rear Object Sensor Signal | B0961 06 | B0961 06 | B0961 01 | B0961 08, B0961 21 |
Low Reference | -- | 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 8 V to the object sensors via the 8 V reference circuit and provides ground via the low reference circuit. The object alarm module triggers the sensors in a sequential loop. After each sensor transmits, the object alarm module uses the sensor ring received though the signal circuit to calculate the distance and position of an object.
Conditions for Running the DTC
| • | Ignition ON |
| • | The parking assist is activated. The activation takes place through putting in the reverse gear or through operating the parking assist switch. |
Conditions for Setting the DTC
B138A 03
The object alarm module has detected the 8 V reference circuit is less than 7.2 V.
B138A 07
The object alarm module has detected the 8 V reference circuit is greater than 9.2 V.
Action Taken When the DTC Sets
| • | The parking assist is disabled. |
| • | The parking assist indicator in the instrument panel cluster will be activated. |
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
LINK 142605
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, activate the parking assist, observe the scan tool Park Assist Sensor Reference Voltage parameter. The reading should be between 7.2-9.2 V.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at each of the object sensors.
- Ignition ON, activate the park assist, test for 7.5-9.0 V between B78G Object Alarm Sensor - Left Rear Outer the 8 V reference circuit terminal 1 and ground.
- Connect each object sensor one at a time while monitoring the scan tool Park Assist Sensor Reference Voltage parameter. The parameter should be 7.2-9.2 V.
- If all circuits test normal, replace the K41 Object Alarm Module.
| ⇒ | If less than the specified range, test the 8 V reference circuit for a short to ground. If the circuit tests normal, replace the K41 Object Alarm Module. |
| ⇒ | If greater than the specified range, test the 8 V reference circuit for a short to voltage. If the circuit tests normal, replace the K41 Object Alarm Module. |
| ⇒ | If not within the specified range, replace the appropriate object alarm sensor.. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for object alarm module replacement, setup and programming |
