Transmission Controls With PCM

Diagnostic Chart:

Wiring Diagram:

HOLD MODE VOLTAGE LOW
On 1991 and 1992 vehicles the amount of electrical current required to energize an actuator is greater than the amount of current required to hold an actuator in the closed position. Hold mode is a feature built into the PCM that reduces current draw of the 2nd, 3rd, and 4th actuators when these clutches are being held off.

DTC PARAMETERS
DTC 48 is set when the PCM has detected the following condition twice per ignition cycle.
^ Hold mode voltage monitored at terminal J3E13 on the PCM below 6.8 volts.

TEST DESCRIPTION
Numbered steps below refer to steps on trouble chart.
1. This step verifies problem is still present.
2. A ground in circuit 1532 will cause the hold mode fuse to fail.
3. This verifies circuit 1532 is grounded.
4. This step indicates a ground in circuit 1532 or a faulty PCM.
5. If circuit 1532 is open DTC 48 will be set. This step checks circuit 1532 for opens.

DIAGNOSTIC AIDS
When attempting to diagnose an intermittent problem use the Scan tool* to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

* Select MALF History from Scan tool Transmission Control Module (TCM) menu.

Check the tightness of the female terminal grip with a spare male terminal.

When the PCM detects a fault in the circuit (open, ground, short) the PCM will open the circuit internally to protect the circuit.