Refer to Engine Controls Schematics
Indicators
Circuit Description
Ignition voltage is supplied directly to the malfunction indicator lamp (MIL). The powertrain control module (PCM) 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 PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM 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 a DTC to set.
Diagnostic Aids
| • | An open gauge fuse will cause the entire IP cluster to be inoperative. |
| • | If the ignition feed circuit is suspected of being open, check if other bulbs on that circuit illuminate. |
| • | Inspect for any circuitry that is suspected of causing an intermittent complaint for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wiring connections |
| - | Physical damage to the wiring harness |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Important: If the I/P is completely inoperative, refer to Wiring Repairs in Wiring Systems.
Command both the ON and the OFF states. Repeat the commands as necessary.
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If you do not find trouble in the control circuit or the connection at the PCM, the PCM may be faulty. However, this is an extremely unlikely failure.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||
Does the lamp turn ON and OFF with each command? | -- | Go to Diagnostic Aids | ||||||||
3 |
Is the lamp OFF? | -- | ||||||||
4 | Probe the lamp control circuit in the PCM harness connector with a fused jumper wire connected to ground. Is the lamp ON? | -- | ||||||||
5 | Repair the short to ground in the lamp control circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||
6 | Check the connections at the PCM. Did you find and correct the condition? | -- | ||||||||
7 | Check for the following conditions:
Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||
|
Important:: Program the new PCM. Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | -- | ||||||||
9 |
Is the MIL ON? | 10 seconds | ||||||||
10 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
