For 1990-2009 cars
Instrument Cluster Components
Instrument Cluster Ignition Voltage and Indicators 1 of 3

### 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) 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 Instrument Cluster stores DTC B1487 in memory.

• | The volts indicator will illuminate.

### Conditions for Clearing the DTC

• | All instrument cluster history codes will be cleared after 100 ignition cycles (from OFF to RUN) with no current codes active during the 100 ignition cycles.

• | The instrument cluster goes to sleep. The cluster reinitializes with the fault cleared.

• | Use the scan tool.

### Diagnostic Aids

• | When the diagnostics direct you to take electrical measurements at the terminal assignments of the Wiring Harness Junction Blocks, refer to Power Distribution. This measurement is for terminal assignments of the Wiring Harness Junction Blocks.

• | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This may often cause the malfunction to appear.

An intermittent may be caused by any of the following conditions:

• | A poor connection

• | Wire insulation that has been rubbed through

• | A broken wire inside the insulation

Inspect for a poor connection of a damaged harness. Inspect all of the harnesses and connectors for the following conditions:

• | Improper mating

• | Broken locks

• | Improperly formed or damaged terminals

• | Poor terminal-to-wire connections

• | Damaged harnesses

### Test Description

The numbers listed below refer to the numbers on the diagnostic table.

1. This step determines if the 225 circuit has a B+ voltage applied.

2. This step determines if CKT 225 has a short to ground condition.

3. This step determines if CKT 225 has a open circuit condition.

4. 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 Instrument Cluster System Check performed? | -- | Go to Step 2 | Go to Instrument Cluster System Check
2 |

1. The engine is running for more than one minute.
2. Use the J 39200 DMM in order to measure the voltage in circuit 225, by backprobing between the generator harness connector terminal B and ground.

Is the measured voltage equal to the specified value?

B+

Go to Step 9

Go to Step 3

3 |

1. Disconnect the generator connector.
2. Disconnect the Powertrain Control Module (PCM) connector C2 (connector C1 for LD9).
3. Use the J 39200 DMM in order to measure the resistance in CKT 225 between the generator connector terminal B and ground.

Is the measured resistance equal to the specified value?

∞

Go to Step 4

Go to Step 7

4 |

1. Reconnect all of the disconnected components.
2. Leave the engine running longer than one minute.
3. Use the J 39200 DMM in order to measure the voltage in CKT 225 between the generator connector terminal B and ground.

Is the measured voltage equal to the specified value?

B+

Go to Step 5

Go to Step 6

5 | Use the Scan Tool in order to read the Powertrain Control Module (PCM) L-terminal input. Is the L-terminal input high? | -- | 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 Powertrain Control Module (PCM) connector C2 terminal 61 LA1 (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 Powertrain Control Module (PCM). Refer to Powertrain Control Module Replacement (2.4L) or Powertrain Control Module Replacement/Programming (3.4L) 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? | -- | Go to Instrument Cluster System Check | --