Circuit Description
This DTC determines if a fault exists that renders the generator L-terminal continuously low with the engine running.
Conditions for Setting the DTC
| • | All of the following conditions must be met: |
| • | The vehicle is running. |
| • | The powertrain control module (PCM) sends an engine is running class 2 serial data message. |
| • | The PCM does not send the L terminal high class 2 serial data message for 30 seconds after the vehicle has started. |
Action Taken When the DTC Sets
| • | The body control module (BCM) stores DTC B1487 in memory. |
| • | The volts Indicator will illuminate. |
Conditions for Clearing the DTC
| • | All BCM history codes will be cleared after 100 ignition cycles (from OFF to RUN) with no current codes active during the 100 ignition cycles. |
| • | The BCM goes to sleep. The BCM reinitializes with the fault cleared. |
| • | Use the Scan Tool. |
Diagnostic Aids
If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This action may often cause the malfunction to appear.
Test Description
The numbers listed below refer to the numbers on the diagnostic table.
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This step determines if the 225 circuit has 5 Volts applied.
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This step determines if CKT 225 has a short to ground condition.
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This step determines if CKT 225 has a open circuit condition.
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This step determines if the Powertrain Control Module (PCM) is reading the L-terminal status properly.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
|
Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open. | ||||
1 | Was the body control module (BCM) System Check performed? | -- | Go to Step 2 | |
Is the measured voltage equal to the specified value? | 4.5--5.5V | Go to Step 9 | Go to Step 3 | |
Is the measured resistance equal to the specified value? | ∞ | Go to Step 4 | Go to Step 7 | |
Is the measured voltage equal to the specified value? | 4.5--5.5V | Go to Step 5 | Go to Step 6 | |
Use the Scan Tool in order to read the PCM L-terminal input. Does the L-terminal input read inactive? | -- | Go to Step 9 | Go to Step 8 | |
6 | Replace the generator. Refer to Generator Replacement in Engine Electrical. Is the repair complete? | -- | Go to Step 9 | -- |
7 | Repair the short to ground in CKT 225 between the PCM connector C2 terminal 61 (connector C1 terminal 74 for LD9) and the generator connector terminal B. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | Go to Step 9 | -- |
8 | Replace the PCM. Refer to Powertrain Control Module Replacement or Powertrain Control Module Replacement/Programming in Engine Controls. Is the repair complete? | -- | Go to Step 9 | -- |
9 | Clear the DTCs from the memory. Are the DTCs cleared from the memory? | -- | -- | |
