P0730
DTC P0730Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The powertrain control module (PCM) calculates the gear ratio based on the automatic transmission input shaft speed sensor (AT ISS) and output shaft speed sensor (AT OSS) readings. The PCM compares the known transmission gear ratio to the calculated ratio for the selected gear ranges.
If the PCM detects an incorrect transmission gear ratio, then DTC P0730 sets. DTC P0730 is a type C DTC.
Conditions for Running the DTC
^ No MAP sensor DTCs P0106, P0107, or P0108.
^ No TP sensor DTCs P0121, P0122, or P0123.
^ No VSS DTCs P0502 or P0503.
^ No ISS DTCs P0716 or P0717.
^ No TFP manual valve position switch D1C P1810.
^ No 4WD low DTC P1875.
^ The engine is running longer than 7 seconds.
^ The system voltage is 8 - 18 volts.
^ The vehicle speed is greater than 8 km/h (5 mph).
^ The throttle angle is greater than 15 percent.
^ The TFT is greater than 20°C (68°F).
^ No gear range change for greater than 6.0 seconds.
^ The engine torque must be between 108 Nm (80 ft. lbs.) and:
- 6.0L: 542 Nm (400 ft. lbs.)
- 8.1L: 881 Nm (650 ft. lbs.)
^ The engine is running for 7 seconds.
^ The transfer ratio is 0.95-1.05.
Conditions for Setting the DTC
^ The following conditions are met for 10 seconds.
^ The Gear Ratio is one of the following:
- Greater than 2.51 or less than 2.44
- Greater than 1.50 or less than 1.44
- Greater than 1.03 or less than 0.97 - Greater than 2.12 or less than 2.05
Action Taken When the DTC Sets
^ The PCM does not illuminate the malfunction indicator lamp (MIL).
^ The PCM commands maximum line pressure.
^ The PCM freezes shift adapts.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
^ The PCM stores DTC P0730 in PCM history.
Conditions for Clearing the DTC
^ A scan tool clears the DTC from PCM history.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.
Diagnostic Aids
^ A false or incorrect AT VSS or AT 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.
^ DTC P0730 defaults to an elevated line pressure condition which may result in partial TCC apply.
This may produce an idle surge that could stall the engine.
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 manual valve position switch could set DTC P1810.
4. This step tests for correct ratios in each commanded gear.