DTC 29

Codes 28,29 Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION:
The gear switches are located inside the transaxle. They are pressure operated switches, normally closed. The ECM supplies 12 volts through each selected circuit to the switch. As road speed increases, hydraulic pressure applies the specific gear clutches and the gear switch opens. At this time, the ECM monitors a high, 12 volt potential, and interprets this to indicate that gear is applied. The ECM uses the gear signals to control fuel delivery and TCC.

Code 28 will set if:

^ CKT 108 indicates ground or closed switch for 12 seconds when vehicle is in 4th gear operation TCC locked.
^ No Code 38 or 39.
^ Brake not applied.
OR
^ CKT 108 indicates an open (drive) when the engine is first started.

Code 29 will set if:

^ CKT 446 indicates ground or closed switch for 10 seconds when vehicle is in 4th gear operation.
^ No Code 38 or 39.
^ Brake not applied.
OR
^ CKT 446 indicates an open (drive) when the engine is first started. Codes 28 and 29 don not illuminate the SES light.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Must use a DVM. A test light will not light due to the very low current being supplied by the ECM.

2. Checks to see if CKT is grounded through the switch.

3. Checks for a good, properly operating switch and checks CKT within transaxle for an improper ground.

DIAGNOSTIC AIDS:

^ An intermittent may be caused by a poor connection, mis-routed harness, rubbed through wire insulation, or a wire broken inside the insulation.

Check For:

^ Poor Connection at ECM pins. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ Mis-routed Harness Inspect wiring harness to insure that it is not too close to high voltage wires, such as spark plug leads.
^ Damaged Harness Inspect harness for damage. If harness appears OK, "Scan" while moving related connectors and wiring harness. A change in display would indicate the intermittent fault location.