Reading and Clearing Diagnostic Trouble Codes

Data Link Connector:

When trying to verify a speed control system electronic malfunction: Connect a DRB scan tool if available to the data link connector The connector is located below the steering column, and at lower edge of the panel.

1. A speed control malfunction may occur without a diagnostic code being indicated.

Refer to for further informtion and usage of the DRB scan tool and a more complete list of Diagnostic Trouble Code.

Speed Control Diagnostic Trouble Codes:

Speed Control Slows Down By Itself
Test vehicle speed sensor, refer to Instrument Panel, Gauges and Warning Indicators/Instrument Panel. If sensor fails replace sensor, If it passes perform the following test:
1. Perform the speed control switch test (in the Powertrain Diagnostic) on the DECEL switch, if it fails replace switch.
2. If the switch passes, conduct the vacuum supply test.
3. If it passes, conduct the servo vacuum test. If it fails replace servo.
4. If servo passes, replace the PCM.

Speed Control Electrical Test
Electronic speed control systems may be tested using two different methods. One involves use of a DRB. If this test method is desired, refer to the Powertrain Diagnostic Test Procedures for charging and speed control system.

The other test method uses a volt/ohm meter. The volt/ohm meter method is described in the following tests.

Speed Control Circuit:

If any information is needed concerning wiring.

CAUTION: When test probing for voltage or continuity at electrical connectors, care must be taken not to damage connector, terminals, or seals. If these components are damaged, intermittent or complete system failure may occur.

When electrical connections are removed, corrosion should be removed from electrical terminals and a light coating of Mopar Multi-Purpose Grease, or equivalent, applied. Inspect connectors for damage terminals.

A poor connection can cause a complete or intermittent malfunction and is also the only connection in the circuit, that can not be tested. For this reason, a loose connection may be misdiagnosed as a component malfunction.