P0730

Incorrect Gear Ratio:

Gear Ratios:

Incorrect Gear Ratio:

Incorrect Gear Ratio (continued):

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) calculates gear ratio based on data from the Automatic Transmission Input (Shaft) and Output (Shaft) Speed sensors. The PCM compares the known transmission gear ratio to a calculated ratio for each gear range selected.

DTC P0730 sets if the steady state adapts are at their maximum and the PCM detects an incorrect gear ratio because of excessive slip within the transmission. DTC P0730 is a Type C DTC.

CONDITIONS FOR SETTING THE DTC

^ No Mass Air Flow (MAF) DTCs P0101, P0102 or P0103 are set.

^ No Throttle Position (TP) DTCs P0121, P0122 or P0123 are set.

^ No Vehicle Speed Sensor (VSS) DTCs P0502 or P0503 are set.

^ No A/T Input Speed Sensor (ISS) DTCs P0716 or P0717 are set.

^ No 1-2 shift solenoid valve electrical DTC P0753 is set.

^ No 2-3 shift solenoid valve electrical DTC P075B is set.

^ No Transmission Fluid Pressure (TFP) Val Position Sw. DTC P1810 is set.

^ Engine running for more than 5 seconds.

^ The vehicle speed is greater than ii km/h (7 mph).

^ The throttle angle is greater than 15.7°.

^ The automatic transmission range switch is not indicating park or neutral.

^ At least one steady state adapt cell is at maximum.

^ The transmission fluid temperature is greater than 20°C (68°F).

^ Delivered torque is greater than 135 Nm (100 lb ft).

^ All of the following fail cases are true for 4 seconds:

- First gear ratio is less than 2.87 or greater than 3.11.

- Second gear ratio is less than 1.54 or greater than 1.71.

- Third gear ratio is less than 0.95 or greater than 1.05.

- Fourth gear ratio is less than 0.65 or greater than 0.71.

- Reverse gear ratio is less than 2.02 or greater than 2.23.

ACTION TAKEN WHEN THE DTC SETS

^ SERVICE TRANSMISSION displays on the Driver Information Center (DIC).

^ The PCM commands maximum line pressure.

^ The PCM disable steady state adapts.

^ The PCM disable upshift adapts.

^ The PCM disable garage shift adapts.

^ The PCM inhibits torque management.

CONDITIONS FOR CLEARING THE DIC/DTC

^ The PCM sees a correct gear ratio in each gear range for 4 seconds.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

DIAGNOSTIC AIDS

Ensure that the vehicle's final drive ratio matches Programmable Read Only Memory (PROM) calibration.

TEST DESCRIPTION

The numbers below refer to the steps on the diagnostic chart.

1. This Step ensures that you performed the Powertrain On-Board Diagnostic System Check.

2. This Step verifies that you inspected the transmission fluid and that the fluid is at the proper level. An under-filled transmission could result in insufficient hydraulic line pressure causing the transmission to slip.

3. This Step inspects for additional DTCs. If a VSS or A/T ISS DTC is set, refer to those DTC charts first. Testing and Inspection

5. This Step installs the J21867 Pressure Gauge along with the J 21867-94 Line Pressure Fitting. With the engine running (in Park), control the amount of current through the Pressure Control Solenoid Valve (PC Sol. Valve) while monitoring the pressure gauge.

7. This Step replaces the Pressure Control Solenoid Valve which caused the high line pressure.

9. This Step inspects and either replaces or repairs the faulty components that caused the low line pressure.

10. Set the scan tool in snapshot mode. Monitor the following three parameters:

Important: When driving the vehicle in Reverse, the commanded gear will be first.

^ Automatic Transmission Fluid Pressure Manual Valve Position switch (TFP Val. Position Sw.)

^ Transmission gear ratio

^ Commanded gear

11. This Step inspects the reverse clutch and LO reverse band for slippage when the vehicle is placed in Reverse and the ratio is too high (2.22).

13. This Step inspects the valve body for hydraulic failure when the vehicle was placed in Reverse (2.02).

14. This Step instructs the technician to drive the vehicle with the gear select lever in the Overdrive range. Compare the snapshot data with the value column.

17. This Step inspects and repairs the faulty components that caused a ratio greater than 1.05.

19. This Step inspects and repairs the faulty components that caused a ratio greater than 1.71.

21. This Step inspects and repairs the faulty components that caused a ratio greater than 1.54.

23. This Step inspects and repairs the faulty components that caused a ratio greater than 2.87.

24. This Step instructs the technician to drive the vehicle with the gear select lever in the D3 range. Compare the snapshot data with the value column.

25. This Step inspects and repairs the faulty components that caused a ratio less than 0.95.

27. This Step inspects and repairs the faulty components that caused a ratio that was less than 0.95 but greater than 0.71.

29. This Step inspects and repairs the faulty components that caused a ratio greater than 1.05.

31. This Step inspects and repairs the faulty components that caused a ratio greater than 1.71.

33. This Step inspects and repairs the faulty components that caused a ratio less than 1.54.

35. This Step inspects and repairs the faulty components that caused a ratio less than 2.87.

36. This Step instructs the technician to drive the vehicle with the gear select lever in the D2 range. Compare the snapshot data with the value column.

37. This Step inspects and repairs the faulty components that caused a ratio less than 1.54.

39. This Step inspects and repairs the faulty components that caused a ratio greater than 1.05.

41. This Step inspects and repairs the faulty components that caused a ratio greater than 1.71.

43. This Step inspects and repairs the faulty components that caused a ratio less than 1.54.

45. This Step inspects and repairs the faulty components that caused a ratio less than 2.87.

46. This Step instructs the technician to drive the vehicle with the gear select lever in the D1 (low) range. Compare the snapshot data with the value column.

47. This Step inspects and repairs the faulty components that caused a ratio less than 2.87.

49. This Step inspects and repairs the faulty components that caused a ratio greater than 3.11.

50. This Step replaces the PCM after you inspect the components.