Manual Transmission

Diagnostic Trouble Code (DTC) 84:

Skip Shift Solenoid Circuit:

CIRCUIT DESCRIPTION
Ignition voltage is supplied to the skip shift solenoid on CKT 541. The Powertrain Control Module (PCM) controls solenoid operation by providing the ground path for CKT 587. During certain light load operating conditions the PCM energizes the skip shift solenoid which is mounted on the transmission. When this system is enabled, it is possible to shift from 1st gear to 4th gear only. This maximizes fuel economy.

The skip shift solenoid will be enabled if all of the following conditions are met.

- Engine running.
- Vehicle speed greater than 15 mph but less than 21 mph.
- Throttle position less than 35%.
- Engine coolant temperature greater than 77°C (171°F).
- BARO greater than 76 kPa.

The PCM uses the measured RPM and the vehicle speed to calculate what gear the vehicle is in. It is this calculation that determines when the skip shift solenoid should be turned "ON."

The skip shift (if all above criteria are met) will occur only once per upshift cycle. The skip shift system is not re-enabled unless vehicle speed drops below 1 mph.

DTC 84 WILL SET WHEN
The PCM detects the wrong voltage potential on CKT 587 for 26 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
DTC 84 will be stored in the PCM memory but will not turn "ON" the Malfunction Indicator Lamp (MIL).

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test determines if the device can be controlled by the PCM.
2. This check can detect a partially shorted coil which would cause excessive current flow. If excessive current flow is detected, a circuit check will be performed to isolate the device from the wiring. Leave the circuit energized for 2 minutes to allow the coil to warm up. The coil may open (amps drop to "0") when warm.
3. The remaining circuit checks will identify a circuit problem that has caused an excessive current flow or inoperative solenoid.

DIAGNOSTIC AIDS
Inspect the harness and all related connectors including connections at the PCM. These may cause an intermittent. Check for damaged or pushed out terminals.