Go to Engine Controls Schematic
Cell 23: PCM Power and Grounding, MIL, and DLC
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Circuit Description
There should always be a steady Malfunction Indicator Lamp (MIL) when the ignition is ON and engine OFF. Battery ignition voltage is supplied to the lamp. The PCM will turn the lamp ON by grounding the ignition feed circuit.
Diagnostic Aids
If the engine cranks but will not run, check:
| • | Continuous battery-fuse or fusible link for open. |
| • | PCM ignition fuse for open. |
| • | Battery Feed circuit to PCM for open. |
| • | Ignition Feed circuit to PCM for open. |
| • | Poor connection to PCM. |
Test Description
The number(s) below refer to step number(s) on the Diagnostic Table.
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This step will isolate the problem in the MIL control circuit.
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If the Battery Feed, Ignition Feed and Diagnostic Test circuits have voltage, the PCM connections, grounds, or PCM are malfunctioning.
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Refer to PCM terminal end view in this section for PCM pin locations of ground circuits.
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If the fuse/fusible link is open, refer to PCM Wiring Diagram for complete circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool Capture Info function to save the Freeze Frame and the Failure records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic ((OBD) System Check | -- | ||
2 | Attempt to start the engine. Does the engine start? | -- | ||
3 | Check the fuse number 4. Is the fuse OK? | -- | ||
4 | Turn the ignition ON. Probe the ignition feed circuit at the cluster connector with an J 35616-200 unpowered test lamp to ground. Is the test lamp ON? | -- | ||
Is the MIL ON? | -- | |||
Check the PCM Ignition Feed and Battery Feed fuses. Are both of the fuses OK? | -- | |||
7 |
Is the test lamp ON both circuits? | -- | ||
Did you perform a repair? | -- | |||
9 |
Did you perform a repair? | -- | ||
10 |
Did you perform a repair? | -- | ||
11 | Repair the open in the ignition feed circuit to the cluster connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
Locate and repair the open in the PCM battery feed circuit or the PCM ignition feed circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | ||
13 | Locate and repair the short to ground in the PCM ignition feed circuit or the PCM battery feed circuit as necessary. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
14 | Locate and repair the short to ground in the instrument cluster ignition feed circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
15 | Replace the PCM. Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
16 |
Did you perform a repair? | -- | ||
17 |
Is the bulb OK? | -- | ||
18 | Replace the MIL bulb. Is the action complete? | -- | -- | |
19 | Replace the instrument cluster. Is the action complete? | -- | -- | |
20 | Operate the vehicle within the conditions that the sypmtom was noted. Does the system operate properly? | -- |
