For 1990-2009 cars

Table 1: | 4T65-E Range Reference, modified for use as P0730 Thumbnail
Table 2: | DTC P0730 Incorrect Gear Ratio

#### 4T65-E Range Reference, modified for use as P0730 Thumbnail

| Reverse | D | 3 | 2 | 1
--- | --- | --- | --- | --- | ---
Gear |  | 1st | 2nd | 3rd | 4th | 1st | 2nd | 3rd | 1st | 2nd | 1st
Fourth Clutch | -- | -- | -- | -- | A | -- | -- | -- | -- | -- | --
Reverse Band | A | -- | -- | -- | -- | -- | -- | -- | -- | -- | --
Second Clutch | -- | -- | A | A | A | -- | A | A | -- | A | --
Third Clutch | -- | -- | -- | A | A* | -- | -- | A | -- | -- | A
Third Sprag | -- | -- | -- | H | O | -- | -- | H | -- | -- | H
Input Clutch | A | A | A* | -- | -- | A | A* | A | A | A* | A
Input Sprag | H | H | O | -- | -- | H | O | H | H | O | H
2-1 Manual Band | -- | -- | -- | -- | -- | -- | -- | -- | A | A | A
1-2 Support Roller Clutch | -- | H | H | O | O | H | H | O | H | H | H
Forward Band | -- | A | A | A* | A* | A | A | A* | A | A | A

- A = Applied
- H = Holding
- O = Overrun
- * = applied with no load (not transmitting torque)

### Circuit Description

The PCM calculates the gear ratio based on data from the automatic transmission input shaft speed (A/T ISS) sensor and the vehicle speed sensor (VSS). The PCM compares the known transmission gear ratio to a calculated ratio for each gear range selected. The VSS output is translated to RPM and mph by the PCM for various uses.

If the PCM detects an incorrect gear ratio because of excessive slip within the transmission, then DTC P0730 sets. DTC P0730 is a type D DTC.

### Conditions for Running the DTC

• | No TP sensor DTCs P0121, P0122 or P0123 are set.

• | No VSS DTC P0502 or P0503 is set.

• | No A/T ISS sensor DTC P0716 or P0717 is set.

• | No TFP manual valve position switch DTC P1810 is set.

• | The engine speed is greater than 500 RPM for 5 seconds and not in fuel shut off.

• | The transmission is not in PARK or NEUTRAL.

• | The TP angle is greater than 14%.

• | The vehicle speed is greater than 11 km/h (7 mph).

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

• | The engine torque is 70-270 N·m (50-200 lb ft).

• | The time since the last gear range change is greater than 3 seconds.

### Conditions for Setting the DTC

DTC P0730 sets when one of the following conditions occurs for 7 seconds:

• | The gear ratio is more than 2.97:1.

• | The gear ratio is 2.43:1 to 2.87:1.

• | The gear ratio is 1.62:1 to 2.33:1.

• | The gear ratio is 1.05:1 to 1.52:1.

• | The gear ratio is 0.75:1 to 0.95:1.

### 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 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 consecutive 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

• | Inspect for intermittent A/T ISS sensor or VSS circuit conditions.

• | Inspect for an incorrect calibration.

• | 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.

1. This step tests for low fluid level, which may cause slipping and result in an undefined gear ratio.

2. This step verifies that the correct gear ratios occur for commanded gears.

3. This step tests for low line pressure.

#### DTC P0730 Incorrect Gear Ratio

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls
2 | Visually inspect the transmission cooling system for fluid leaks. Refer to Fluid Leak Diagnosis . Was a condition found? | -- | Go to Step 7 | Go to Step 3
3 | Was the transmission fluid checking procedure performed? | -- | Go to Step 4 | Go to Transmission Fluid Check
4 |

1. Install the Scan Tool .
2. Start the engine.

Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the PCM.

3. Record the Failure Records.
4. Clear the DTCs.
5. Use the scan tool snapshot mode in order to record the transmission gear ratios.
6. Drive the vehicle in transmission gear ranges 1, 2, 3 and D with the TP angle greater than 14% and the vehicle speed greater than 11 km/h (7 mph) for 7 seconds.
7. Record each transmission gear.

Did the commanded gear ratio match the specified ranges?

Reverse: 2.33:1 to 2.43:1

1st: 2.87:1 to 2.97:1

2nd: 1.52:1 to 1.62:1

3rd: 0.95:1 to 1.05:1

4th: 0.65:1 to 0.75:1

Go to Diagnostic Aids

Go to Step 5

5 | Perform the line pressure check. Refer to the Line Pressure Check . Was a condition found? | -- | Go to Symptom Diagnosis | Go to Step 6
6 | Inspect for clutch slippage. Refer to Symptom Diagnosis . Was a condition found and corrected? | -- | Go to Step 8 | --
7 | Repair the transmission cooling system as necessary. Refer to Fluid Leak Diagnosis . Is the repair complete? | -- | Go to Step 8 | --
8 | Perform the following procedure in order to verify the repair:

1. Select DTC.
2. Select Clear Info.
3. Road test the vehicle with the TP angle greater than 14% and the vehicle speed greater than 7 mph.
4. Monitor TP angle and gear ratio on the scan tool. Ensure that any one of the gear ratio values are obtained for at least 7 seconds.
5. Select Specific DTC.
6. Enter DTC P0730.

Has the test run and passed?

Reverse: 2.33:1 to 2.43:1

1st: 2.87:1 to 2.97:1

2nd: 1.52:1 to 1.62:1

3rd: 0.95:1 to 1.05:1

4th: 0.65:1 to 0.75:1

System OK

Go to Step 1