Transmission Controls With PCM

Diagnostic Chart:

Wiring Diagram:

SELECTOR SWITCH - INVALID DATA
The PCM determines which gear is selected by a combination of opens and grounds in circuits 771, 772, and 773 at the selector switch. Each combination indicates a specific selection on the manual shift quadrant (P, R, N, D, 2, or 3). Circuit 776 is either open or grounded to produce an even number of grounded circuits (771 772, 773, and 776). Invalid data indicates that the sum of the grounded circuits 771, 772, 773 and 776, in one of the manual shift quadrants is equal to a odd number.

DTC PARAMETERS
DTC 49 is set when the PCM has detected the following conditions twice per ignition cycle.
^ An invalid bit pattern for more than 3.5 seconds.

The difference between DTC 49 and DTC 46 is that a possible bit pattern error due to misadjustment could set a DTC 49.

TEST DESCRIPTION
1. This step verifies the conditions for DTC 49 still exist.
2. If the shift cable or switch is misadjusted, a DTC 49 may set while in certain gear shift positions.
3. DTC 49 may set due to one or more circuits being shorted to ground. By disconnecting the switch, the PCM should read all circuits as high and the Scan tool should display "OPEN."
4. This step will isolate an open circuit. As each individual circuit is grounded, the PCM/TC should see the low signal and the tool should display "INVALID."
5. The PCM/TC supplies a 12 volt signal to each selector switch circuit. This step tests for that voltage.
6. DTC 49 may have been set due to one of the circuits being shorted to voltage. This step verifies if short to voltage exists.

DIAGNOSTIC AIDS
* 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.

If no circuit problems can be detected, check shift cable and switch adjustment.
^ This code will cause the transaxle to start out in 2nd gear.