Circuit Description
The ignition mode switch has 3 LEDs that indicate the vehicle power mode. When the vehicle is in the Off mode, the Off LED may illuminate. Pressing the lower button of the ignition mode switch, the vehicle enters the accessory mode and ACC LED will illuminate. Keeping the lower button pressed for about 5-6 seconds, the vehicle enters run mode with the engine off and the START LED will illuminate. All these LEDs have the voltage supplied from the body control module (BCM) through the ignition mode switch supply voltage circuit. The ground path for each LED is controlled by the BCM.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B0976 Off Indicator Control Circuit |
| • | DTC B0977 Start Indicator Control Circuit |
| • | DTC B0978 Accessory Indicator Control Circuit |
DTC Symptom | DTC Symptom Descriptor |
|---|---|
01 | Short to battery |
06 | Short to ground or open |
Conditions for Running the DTC
Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.
Conditions for Setting the DTC
B0976 01
| • | The BCM detects a short to battery in the off indicator control circuit. |
| • | The above condition exists for more than 5 seconds. |
B0977-B0978 01
| • | The BCM detects a short to battery in the respective indicator control circuit, when the output is active. |
| • | The above condition exists for more than 1 second. |
B0976-B0978 06
| • | The BCM detects an open or short to ground in the respective indicator control circuit, when the output is inactive. |
| • | The above condition exists for more than 1 second. |
Action Taken When the DTC Sets
B0976-B0978 01
The BCM disables the respective output until the next ignition cycle.
Conditions for Clearing the DTC
| • | A current DTC clears when the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
If more than one DTC were retrieved, the fault condition is common for all circuits.
-
A LED that illuminates, assures that the fault is not internal to the ignition mode switch.
-
A B0976 requires vehicle in OFF mode, a B0977 requires ignition ON with the engine OFF and a B0978 requires vehicle in accessory mode.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Power Distribution Schematics and Body Control System Schematics Connector End View Reference: Master Electrical Component List | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 | Was the DTC B2625 retrieved as current? | -- | Go to DTC B2625 | Go to Step 3 |
Did you record at least two of the DTCs B0976, B0977 or B0978? | -- | Go to Step 4 | Go to Step 7 | |
4 |
Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 5 |
5 |
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 6 |
6 | Test the battery supply voltage circuit to C3-A7 cavity for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
Does the LED related to the DTC retrieved illuminate all the time? | -- | Go to Step 9 | Go to Step 8 | |
Is the value measured within the specified range? | B+ | Go to Step 9 | Go to Step 12 | |
9 |
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 |
10 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 11 |
11 | Replace the BCM . Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 14 | -- |
12 | Inspect for poor connections at the harness connector of the ignition mode switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs . Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 |
13 | Replace the ignition mode switch. Refer to Ignition and Start Switch Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- |
14 |
Does the DTC reset? | -- | Go to Step 1 | System OK |
