P0730

CIRCUIT DESCRIPTION

The Vehicle Control Module (VCM) calculates the gear ratio based on the Automatic Transmission Input Shaft Speed (A/T ISS) and Output Shaft Speed (OSS) Sensor readings. The VCM compares the known transmission gear ratio to the calculated ratio for the selected gear ranges.

If the VCM detects an unknown transmission gear ratio, then DTC P0730 sets. DTC P0730 is a type D DTC.


CONDITIONS FOR SETTING THE DTC

The following conditions are met for 10 seconds.

^ No Manifold Absolute Pressure (MAP) DTCs P0106, P0107, or P0108.

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

^ No OSS DTC P0502 or P0503.

^ No A/T ISS DTCs P0716 or P0717.

^ No Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) DTC P1810.

^ The Vehicle Speed is greater than 7 km/h (4 mph).

^ The TP Angle is greater than 15%.

^ The TFT is greater than 20°C (68°F).

^ 30 seconds must have elapsed since the last gear range change.

^ The engine torque is 110 N.m (80 lb. ft) 5.7L and 7.4L or 95 N.m (70 lb. ft) 4.3L to the following:

- 405 N.m (300 lb. ft)

- 542 N.m (400 lb. ft) 5.7L

- 677 N.m (500 lb. ft) 7.4L

^ The engine is running greater than 475 RPM for 5 seconds.

^ The Gear Ratio is one of the following:

- Greater than 2.50 or less than 2.42

- Greater than 1.50 or less than 1.44

- Greater than 1.03 or less than 0.25

- Greater than 2.12 or less than 2.04

ACTION TAKEN WHEN THE DTC SETS

^ The VCM does not illuminate the Malfunction Indicator Lamp (MIL).

^ The VCM commands maximum line pressure.

^ The VCM freezes shift adapts.

^ DTC P0730 is stored in VCM history.


CONDTIONS FOR CLEARING THE DTC

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

^ The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.

DIAGNOSTIC AIDS

^ First diagnose and clear any engine DTCs or TP Sensor codes that are present. Then inspect for any transmission DTCs that may have reset.

^ A false or incorrect A/T OSS or A/T ISS signal can set DTC P0730.

^ DTC P1870 detects an incorrect gear ratio in fourth gear with TCC applied.

^ Inspect for any improperly installed after-market equipment.

^ Sticking or contamination of shift valves may cause intermittent incorrect gear ratios.

^ Refer to the Shift Solenoid Valve State and Gear Ratio table.

TEST DESCRIPTION

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

3. This step tests the indicated range signal to the actual selected range. A faulty TFP Val. Position Sw. could set DTC P1810.

4. This step tests for proper ratios in each commanded gear state.