For 1990-2009 cars

### Circuit Description

This DTC is used to monitor the voltage level available to the cruise control module. If the voltage level drops below 10 Volts at terminal 9 (BLK/YEL wire), DTC 42 will set.

### Diagnostic Aids

Check for the following:

• | Open or high resistance in the BLK/YEL wire.

• | Open, high resistance or low voltage in the power distribution to the ECU-IG fuse in junction block 2.

• | Open or high resistance in the WHT/BLK wire.

• | Open or high resistance in the ground distribution to splice pack 250/G203

• | Vehicle charging system for poor performance.

• | Faulty cruise control module.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Inspect the following harness connectors for backed out terminals, improper mating, broken lock, improperly formed or damaged terminals or for poor terminal-to-wire connection before replacing the suspect component:

• | Cruise control module connector

• | Junction block 2 C4

• | Splice pack 250

• | Ignition switch

### Test Description

The number(s) below refer to the step number(s) in the diagnostic table.

1. This step tests the condition of the vehicles charging system.

2. This step tests the condition of the power feed circuit to the module.

3. This step tests for a faulty cruise control module.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Cruise Control Schematics
1 | Did you perform the Diagnostic System Check - Cruise Control ? | -- | Go to Step 2 | Go to Diagnostic System Check - Cruise Control
2 |

1. Start the engine.
2. Turn the headlamps on to high beams.
3. Set the blower fan speed to high.
4. Measure the voltage between the positive and negative battery terminals.

Is the voltage within the specified range?

10-14 V

Go to Step 3

Go to Step 6

3 |

1. Turn the ignition switch to the lock position.
2. Disconnect the cruise control module connector.
3. Re-start the engine.
4. Measure the voltage between cavity 9 and chassis ground

Is the voltage within the specified range?

10-14 V

Go to Step 4

Go to Step 5

4 |

1. Turn the headlamps off.
2. Turn the blower off.
3. Turn OFF the ignition.
4. Reconnect the cruise control module.
5. Test drive the vehicle and engage the cruise control to verify the operation.
6. Stop the vehicle.
7. Remove the STOP fuse.
8. Remove the ECU-B fuse.
9. Wait 30 seconds.
10. Reinstall STOP and ECU-B fuses.
11. Turn ON the ignition, with the engine OFF.
12. Using the jumper, connect the DLC terminals Tc and E1.

Does the CRUISE indicator lamp flash the same trouble code?

--

Go to Step 5

Go to Step 9

5 | Repair the high resistance in the BLK/YEL wire between the module and junction block 2. Refer to Wiring Repairs in Wiring System. Is the repair complete? | -- | Go to Step 10 | --
6 | In order to diagnose a low charging condition, refer to Charging System Test in Engine Electrical Is the action complete? | -- | Go to Step 10 | --
7 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8
8 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Is the repair complete? | -- | Go to Step 10 | --
9 | Malfunction is not present at this time. Refer to diagnostic aids for additional information. Is the action complete? | -- | System OK | --
10 |

1. Turn OFF the ignition.
2. Remove the STOP fuse.
3. Remove the ECU-B fuse.
4. Wait 30 seconds.
5. Reinstall STOP and ECU-B fuses.
6. Turn ON the ignition, with the engine OFF.
7. Using the jumper, connect the DLC terminals Tc and E1.

Does the CRUISE indicator lamp flash the same trouble code?

--

Go to Step 2

System OK