For 1990-2009 cars

### Circuit Description

The body control module (BCM) has designated circuits for monitoring vehicle system voltage. The BCM monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components and incorrect data may occur when the voltage is out of range. The BCM monitors the system voltage over an extended length of time. If the BCM detects the system voltage is outside an expected range for the calibrated length of time, or the BCM battery sense circuits differ by 3 volts, DTC B1517 will set. Other modules also monitor system voltage. The system voltage message is sent to the other modules and will default to 12.9 volts.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1517 Battery Voltage (signal or 1) Voltage

This vehicle has DTCs that include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
52 | Compare Failure

### Conditions for Running the DTC

This DTC shall run only if the BCM has power, ground, and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage.

### Conditions for Setting the DTC

The battery voltage differs by 3 volts on the BCM battery sense circuits for 15 seconds.

### Action Taken When the DTC Sets

The DIC displays the SERVICE VEHICLE SOON Message.

### Conditions for Clearing the DTC

• | The DTC will clear current status when the fault is no longer present.

• | A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

• | Use a scan tool.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step tests for the proper voltage at battery positive voltage sense circuits of the BCM. If voltages are not within the proper operating range, the voltage sense circuits need to be tested.

2. This step tests the ground sense circuits of the BCM.

3. This step tests for the proper voltage of the circuits to the BCM. If voltage is not within the proper operating range, the battery positive voltage and ground circuits of the BCM need to be tested.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Starting and Charging Schematics or Power Distribution Schematics Connector End View Reference: Power and Grounding Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Battery Voltage parameter in the body control module (BCM) data list.

Do any of the voltages differ by more than the specified value?

3 V

Go to Step 5

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the BCM.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage between the battery positive voltage circuits of the BCM and the ground sense circuits at terminal of the BCM.

Do the voltages differ by more than the specified value?

3 V

Go to Step 9

Go to Step 4

4 | Measure the voltage from the battery positive voltage circuits of the BCM to a good ground. Do the voltages differ by more than the specified value? | 3 V | Go to Step 8 | Go to Step 7
5 |

1. Turn OFF the ignition.
2. Measure the voltage between the battery positive voltage circuits of the BCM and the ground circuits of the BCM.

Does the voltage measure greater than the specified value?

3 V

Go to Step 9

Go to Step 6

6 | Measure the voltage between the battery positive voltage circuit of BCM and a good ground. Does the voltage measure greater than the specified value? | 3 V | Go to Step 8 | Go to Step 7
7 | Test the battery positive voltage circuits of BCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9
8 | Test the ground sense circuits for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9
9 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10
10 | Replace the BCM. Refer to Control Module References for BCM replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 11 | --
11 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK