Diagnostic Instructions

DTC Descriptors

DTC B138A 03: Control Module Voltage Reference Output Circuit Low Voltage

DTC 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	B0954 06, B0955 06, B0956 06, B0957 06 -- B0958 06, B0959 06, B0960 06, B0961 06, -- B096C 06, B096D 06, -- B138A 03	B0954 06, B0955 06, B0956 06, B0957 06 -- B0958 06, B0959 06, B0960 06, B0961 06, -- B096C 06, B096D 06	B0954 06, B0955 06, B0956 06, B0957 06 -- B0958 06, B0959 06, B0960 06, B0961 06, -- B096C 06, B096D 06, -- B138A 07	--
Left Front Object Sensor Signal	B0954 06	B0954 06	B0954 01	B0954 08, B0954 21
Left Middle Front Object Sensor Signal	B0955 06	B0955 06	B0955 01	B0955 08, B0955 21
Right Middle Front Object Sensor Signal	B0956 06	B0956 06	B0956 01	B0956 08, B0956 21
Right Front Object Sensor Signal	B0957 06	B0957 06	B0957 01	B0957 08, B0957 21
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
Left Side Object Sensor Signal	B096C 06	B096C 06	B096C 01	B096C 08, B096C 21
Right Side Object Sensor Signal	B096D 06	B096D 06	B096D 01	B096D 08, B096D 21
Low Reference	--	B0954 06, B0955 06, B0956 06, B0957 06 -- B0958 06, B0959 06, B0960 06, B0961 06, -- B096C 06, B096D 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

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

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

Object Detection Schematics

Connector End View Reference

Component Connector End Views

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

1. Ignition OFF, disconnect the harness connector at each of the object sensors.
2. 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.

⇒	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.

3. 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 not within the specified range, replace the appropriate object alarm sensor..

4. If all circuits test normal, replace the K41 Object Alarm Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.