GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using the 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 B0958 01: Parking Aid Rear Sensor 1 Circuit Short to Battery-Left Corner

DTC B0958 06: Parking Aid Rear Sensor 1 Circuit Short to Ground or Open-Left Corner

DTC B0958 08: Parking Aid Rear Sensor 1 Circuit Signal Invalid-Left Corner

DTC B0958 21: Parking Aid Rear Sensor 1 Circuit Incorrect Period-Left Corner

DTC B0959 01: Parking Aid Rear Sensor 2 Circuit Short to Battery-Left Middle

DTC B0959 06: Parking Aid Rear Sensor 2 Circuit Short to Ground or Open-Left Middle

DTC B0959 08: Parking Aid Rear Sensor 2 Circuit Signal Invalid-Left Middle

DTC B0959 21: Parking Aid Rear Sensor 2 Circuit Incorrect Period-Left Middle

DTC B0960 01: Parking Aid Rear Sensor 3 Circuit Short to Battery-Right Middle

DTC B0960 06: Parking Aid Rear Sensor 3 Circuit Short to Ground or Open-Right Middle

DTC B0960 08: Parking Aid Rear Sensor 3 Circuit Signal Invalid-Right Middle

DTC B0960 21: Parking Aid Rear Sensor 3 Circuit Incorrect Period-Right Middle

DTC B0961 01: Parking Aid Rear Sensor 4 Circuit Short to Battery-Right Corner

DTC B0961 06: Parking Aid Rear Sensor 4 Circuit Short to Ground or Open-Right Corner

DTC B0961 08: Parking Aid Rear Sensor 4 Circuit Signal Invalid-Right Corner

DTC B0961 21: Parking Aid Rear Sensor 4 Circuit Incorrect Period-Right Corner

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

8-Volt Reference

B0958 06, B0959 06, B0960 06, B0961 06, B1E3A 07

B0958 06, B0959 06, B0960 06, B0961 06

B1E3A 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 volts to the object sensors via the 8 volt 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

    • DTC B1325 is not set
    • Ignition voltage is between 9-16 volts
    • The vehicle is in REVERSE

Conditions for Setting the DTC

B0958 01, B0959 01, B0960 01, or B0961 01

Voltage seen on the object sensor signal circuit is greater than 11.5 volts.

B0958 06, B0959 06, B0960 06, or B0961 06

Voltage seen on the object sensor signal circuit is less than 0.5 volts.

B0958 08, B0959 08, B0960 08, or B0961 08

An invalid signal is received by the object alarm module.

B0958 21, B0959 21, B0960 21, or B0961 21

The object sensor determines no change in the position of an object while the vehicle is in motion.

Action Taken When the DTC Sets

    • Parking assist is disabled.
    • The object alarm module commands the red indicator ON.
    • The object alarm module sends a serial data message to the instrument panel cluster (IPC) to display SERVICE PARK ASSIST message in the driver information center (DIC) and a chime will sound.

Conditions for Clearing the DTC

    • The DTC will transition to history when the fault is no longer present.
    • A history DTC will clear after 100 malfunction-free ignition cycles.

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

    •  Circuit Testing
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Verify that DTC B1E3A is not set.
  2. If B1E3A is set, refer to DTC B1E3A.
  3. Park brake OFF, transmission in REVERSE, individually place a suitable object behind each sensor. Verify the appropriate scan tool Rear Region parameter is between Zone 1 and Zone 4.

Circuit/System Testing

Single Object Sensor DTC Set

  1. Ignition OFF, disconnect the harness connector at the appropriate object sensor.
  2. Ignition OFF for 30 seconds, test for less than 5 ohms between the low reference circuit terminal 2 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the object alarm module.
  4. Ignition ON, transmission in REVERSE, test for 8.0-9.0 volts between the voltage reference circuit terminal 1 and ground.
  5. If greater than the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the object alarm module.
    If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the object alarm module.
  6. Ignition OFF, remove the malfunctioning object sensor and swap locations with another properly functioning rear object sensor. Connect the harness connector at both sensors.
  7. Ignition ON, verify the DTC is set for the new location in which the malfunctioning sensor is installed.
  8. If the DTC does not set for the new location, test the signal circuit terminal 3 for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the object alarm module.
  9. If the DTC sets for the new location in which the malfunctioning sensor is installed, replace the appropriate rear object sensor.

Multiple Object Sensor DTCs Set

  1. Ignition OFF, disconnect the harness connector at each of the object sensors.
  2. Ignition OFF for 30 seconds, test for less than 5 ohms between the low reference circuit terminal 2 and ground.
  3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the object alarm module.
  4. Ignition ON, transmission in REVERSE, test for 8.0-9.0 volts between the voltage reference circuit terminal 1 and ground.
  5. If greater than the specified range, test the voltage reference circuit for a short to voltage. If the circuit tests normal, replace the object alarm module.
    If less than the specified range, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the object alarm module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Object Sensor Replacement
    •  Control Module References for object alarm module replacement, setup, and programming