P0730

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 MAF DTCs P0101, P0102 or P0103 are set.
^ No Throttle Position (TP) sensor DTCs P0121, P0122 or P0123 are set.
^ No Vehicle Speed (VSS) sensor DTCs P0502 or P0503 are set.
^ No Automatic Transmission Input Speed (A/T ISS) sensor 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 P0758 is set.
^ No Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val Position Sw.) DTC P1810 is set.
^ The engine is not in fuel cut off.
^ Engine running for more than 5 seconds.
^ The time since the gear select lever change is greater than 3 seconds.
^ The throttle angle is greater than 15.7°.
^ The vehicle speed is greater than 11 km/h (7 mph).
^ 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 failure criteria 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 VEHICLE SOON, 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 PROM calibration.
^ Refer to Range Reference table.
^ Refer to Shift Solenoid Valve State and Gear Ratio table.

TEST DESCRIPTION

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

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.
5. This step installs the J 21867 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.

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

10. 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).
11. This step inspects the valve body for hydraulic failure when the vehicle was placed in Reverse (2.02).