Circuit Description
The LEVELING indicator lamp is activated by the automatic level control (ALC) sensor whenever a compress cycle is requested. The sensor provides a switched path to ground. The sensor will flash the lamp when certain DTCs are detected. The sensor will not flash the lamp when this DTC is set.
Conditions for Setting the DTC
The DTC will set when the sensor detects that the lamp output is not externally pulled up to B+ when the sensor output is not active and the ignition signal is high.
Action Taken When the DTC Sets
| • | The sensor's discrete low side output drive for the lamp is disabled. |
| • | The sensor continuously attempts to recover from the fault. |
| • | The LEVELING indicator lamp will not flash. |
Conditions for Clearing the DTC
| • | A current DTC becomes history when conditions for the fault are no longer present and the ignition cycles from OFF to ON. |
| • | A history DTC will clear after 20 ignition cycles. |
| • | Using a scan tool. |
Diagnostic Aids
Check for the following conditions if a history or intermittent DTC is indicated:
| • | A poor connection at the ALC sensor. Inspect the harness connectors for backed out terminals, improper mating, improperly formed or damaged terminals, and poor terminal to wire connections. |
| • | A damaged wiring harness. Inspect the wiring harness for damage. If the wiring harness appears to be in good condition, observe the display on the DMM while moving the connectors and wiring harnesses related to the circuits. A change in the DMM display during this test will indicate the location of the fault. |
| • | For additional information, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | Check the integrity of the LEVELING indicator lamp bulb. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Tests for a short to ground in the control circuit of the LEVELING indicator lamp.
-
Tests for an open in the control circuit of the LEVELING indicator lamp.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Level Control Schematics | ||||
1 | Did you perform the Automatic Level Control (ALC) Diagnostic System Check? | -- | ||
Is the LEVELING indicator lamp illuminated? | -- | |||
3 | Repair a short to ground in the control circuit of the LEVELING indicator lamp. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
Connect a fused jumper wire between the ALC sensor connector terminal G and ground. Is the LEVELING indicator lamp illuminated? | -- | |||
5 | Repair an open in the control circuit of the LEVELING indicator lamp. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
6 |
Important: After replacement calibrate the trim setting for the ALC sensor. Replace the ALC sensor. Refer to Automatic Level Control Sensor Replacement . Is the repair complete? | -- | ||
7 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | |
