P029

DTC PO29: Part 1 Of 2:

DTC PO29: Part 2 Of 2:

Transaxle Solenoid Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the gear ratio and compares the ratio to the commanded gear ratio. If both ratios are not synchronized, Code P029 is set.

TEST CONDITIONS
1. Codes P021, P022, P024, P028 and P056 not set.
2. Transaxle pressure switch indicating D1, D2, D3, or D4 position.
3. Engine running.
4. Vehicle speed 7 mph or greater.
5. Throttle position 11 degrees or greater.

FAILURE CONDITIONS
Case 1:
a. Gear ratio between 0.65 and 0.71 for 5 seconds.
b. 1st gear commanded.

Case 2:
a. Gear ratio between 0.95 and 1.05 for 5 seconds
b. 2nd gear commanded.

Case 3:
a. Gear ratio between 1.54 and 1.71 for 5 seconds.
b. 3rd gear commanded.

Case 4:
a. Gear ratio between 2.87 and 3.11 for 5 seconds.
b. 4th gear commanded.

ACTION TAKEN
1. PCM turns "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon).
2. PCM commands second gear when any forward gear is selected.
3. Garage shift adapts are maintained at current levels.

NOTES ON FAULT TREE:
(Part 1 of 2)
1. Checking if Code P117 also set because it can cause other transaxle problems.
2. Checking if Shift "B" solenoid is "HI" when it should be "LO" or if it is "LO" when it should be "HI."
3. Checking if PCM is operating correctly and setting code falsely.
4. Checking if CKT 741 is open to C129.
5. Checking if CKT 1223 (engine harness side) is open.
6. Checking for a short to ground inside transaxle.
7. Checking for an open inside transaxle.

(Part 2 of 2)
8. Checking CKT 1223 (trans harness side) for a short to voltage inside transaxle.
9. Checking CKT 1223 for a short to voltage from C129 to PCM.
10. Possible causes of getting 4th gear when 1st gear is commanded.
11. Possible causes of getting 3rd gear when 2nd gear is commanded.
12. Possible causes of getting 2nd gear when 3rd gear is commanded.
13. Possible causes of getting 1st gear when 4th gear is commanded.