P0381

DTC P0381

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0381
- Wait To Start Lamp Control Circuit

Diagnostic Fault Information






Circuit/System Description

Ignition voltage is supplied directly to the wait to start indicator. The engine control module (ECM) controls the lamp by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the ECM. When the ECM is commanding a component ON, the voltage of the control circuit should be low, near zero volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the DTC to set.

Conditions for Running the DTC

The ignition voltage is greater than 6 volts but less than 18 volts.

Conditions for Setting the DTC

* The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match.
* The condition must be present for a minimum of 5 seconds.

Action Taken When the DTC Sets

* The ECM stores the DTC information in memory.
* The ECM records the operating conditions at the time the DTC sets. The ECM displays the failure information in the Failure Records on the scan tool.

Conditions for Clearing the DTC

* The history DTC clears after 40 malfunction-free warm-up cycles.
* The DTC becomes history when the conditions for setting the DTC are no longer present.
* The ECM receives the clear code command from the scan tool.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

The wait to start indicator illuminates only with the ignition ON and the engine OFF. The wait to start indicator will not illuminate during post-start glow plug operation. The wait to start indicator will not stay ON for long at higher engine temperatures.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector X2 at the ECM.
2. Ignition ON, verify that the wait to start indicator is OFF.

^ If not OFF, test the wait to start indicator control signal circuit terminal 16 for a short to ground. If the circuit tests normal, replace the instrument panel cluster (IPC).

3. Install a 3-amp fused jumper between the wait to start control signal circuit terminal 16 and ground. Verify that the wait to start indicator is ON.

^ If not ON, test the wait to start indicator control signal circuit terminal 16 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.

4. If all circuits test normal, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Refer to Programming and Relearning. Programming and Relearning