| Table 1: | 4T80-E Range Reference, modified for use as P0730 Thumbnail |
| Table 2: | DTC P0730 Incorrect Gear Ratio |
Range | Reverse | D4 | D3 | D2 | D1 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Gear | R | 1st | 2nd | 3rd | 4th | 1st | 2nd | 3rd | 1st | 2nd | 1st | 2nd |
1-2 Shift Solenoid | ON | ON | OFF | OFF | ON | ON | OFF | OFF | ON | OFF | ON | OFF |
2-3 Shift Solenoid | OFF | OFF | OFF | ON | ON | OFF | OFF | ON | OFF | OFF | OFF | OFF |
Forward | -- | A | A | A | A | A | A | A | A | A | A | A |
Coast | -- | -- | -- | -- | -- | -- | -- | A | A | A | A | A |
3rd Clutch | -- | -- | -- | A | A | -- | -- | A | -- | -- | -- | -- |
2nd Clutch | -- | -- | A | A | A | -- | A | A | -- | A | -- | A |
Reverse | A | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
4th Band | -- | -- | -- | -- | A | -- | -- | -- | -- | A | -- | A |
Lo/Rev Band | A | A | -- | -- | -- | A | -- | -- | A | -- | A | -- |
Lo Roller | -- | H | -- | -- | -- | H | -- | -- | H | -- | H | -- |
2nd Sprag | -- | -- | H | -- | -- | -- | H | -- | -- | H | -- | H |
Forward Sprag | -- | H | H | H | -- | H | H | H | H | H | H | H |
| ||||||||||||
Circuit Description
The 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 Running the DTC
| • | No MAF DTCs P0101, P0102 or P0103. |
| • | No TP DTCs P0121, P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No A/T ISS DTCs P0716 or P0717. |
| • | No 1-2 shift solenoid valve electrical DTC P0753. |
| • | No 2-3 shift solenoid valve electrical DTC P0758. |
| • | No TFP manual valve position switch DTC P1810. |
| • | The engine run time is greater than 5 seconds. |
| • | The engine is not in fuel cut off. |
| • | The automatic transmission range switch is not indicating PARK or NEUTRAL. |
| • | The time since the gear select lever change is greater than 3 seconds. |
| • | The throttle angle is greater than 15.7 degrees. |
| • | The vehicle speed is greater than 11 km/h (7 mph). |
| • | The transmission fluid temperature is greater than 20°C (68°F). |
| • | Delivered torque is greater than 135 N·m(100 lb ft) |
Conditions for Setting the DTC
| • | At least one steady state adapt cell is at maximum. |
| • | One of the following conditions is true for 4 seconds: |
| - | First gear ratio is less than 2.87:1 or greater than 3.11:1. |
| - | Second gear ratio is less than 1.54:1 or greater than 1.71:1. |
| - | Third gear ratio is less than 0.95:1 or greater than 1.05:1. |
| - | Fourth gear ratio is less than 0.65:1 or greater than 0.71:1. |
| - | Reverse gear ratio is less than 2.02:1 or greater than 2.23:1. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | SERVICE VEHICLE SOON, SERVICE TRANSMISSION displays on the driver information center (DIC). |
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes steady state adapts. |
| • | The PCM freezes upshift adapts. |
| • | The PCM freezes garage shift adapts. |
| • | The PCM stores DTC P0730 in PCM history. |
Conditions for Clearing the DIC/DTC
| • | The PCM clears the DIC message when the condition no longer exists. |
| • | The PCM sees a correct gear ratio in each gear range for 1 second. |
| • | A scan tool can clear 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
| • | 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 step numbers on the diagnostic table.
-
This step tests for low fluid level, which may cause slipping, and result in an undefined gear ratio.
-
This step verifies that the correct gear ratios occur for commanded gears.
-
This step tests for low line pressure.
Step | Action | Value(s) | Yes | No | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||||||||||
2 |
Refer to Fluid Leak Diagnosis . Was a condition corrected? | -- | ||||||||||||||||||
Was the Transmission Fluid Checking Procedure performed? | -- | Go to Transmission Fluid Check | ||||||||||||||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the PCM. Did the commanded gear ratio match the specified ranges? | REVERSE: 2.02:1-2.23:1 1st: 2.87:1-3.11:1 2nd: 1.54:1-1.71:1 3rd: 0.95:1-1.05:1 4th: 0.65:1-0.71:1 | Go to Diagnostic Aids | ||||||||||||||||||
Perform the line pressure check. Refer to Line Pressure Check . Was a condition found? | -- | Go to Symptom Diagnosis | ||||||||||||||||||
6 |
Refer to Clutch Plate Diagnosis . Refer to Unit Repair. Is the repair complete? | -- | -- | |||||||||||||||||
7 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
