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For 1990-2009 cars only

DTC P0730 Incorrect Gear Ratio 2.4L

Table 1: Range Reference Table (For DTC P0730)
Table 2: DTC P0730 Incorrect Gear Ratio (2.4L)

Range Reference Table (For DTC P0730)

Range

Park/Neutral

Reverse

D

3

2

1

Gear

N

R

1st

2nd

3rd

4th

1st

2nd

3rd

1st

2nd

3rd**

1st

2nd***

1-2 Shift Solenoid

ON

ON

ON

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

ON

OFF

2-3 Shift Solenoid

OFF

OFF

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

ON

OFF

OFF

2nd Clutch

--

--

--

A

A*

A*

--

A

A*

--

A

A*

--

A

2nd Roller Clutch

--

--

--

H

O

--

--

H

O

--

H

O

--

H

Int./4th Band

--

--

--

--

--

A

--

--

--

--

A

--

--

A

Reverse Clutch

--

A

--

--

--

--

--

--

--

--

--

--

--

--

Coast Clutch

--

--

--

--

--

--

A

A

A

A

A

A

A

A

Input Sprag

--

--

H

H

H

O

H

H

H

H

H

H

H

H

Direct Clutch

--

--

--

--

A

A

--

--

A

--

--

A

--

--

Forward Clutch

--

--

A

A

A

A*

A

A

A

A

A

A

A

A

Lo/Rev Band

A

A

--

--

--

--

--

--

--

--

--

--

A

--

Lo Roller Clutch

--

--

H

O

O

O

H

O

O

H

O

O

H

O

  • A = Applied
  • H = Holding
  • O = Overrunning
  • ON = The solenoid is energized.
  • OFF = The solenoid is de-energized
  • * = Applied with no load
  • ** = Manual Second-Third gear is only available above approximately 100 km/h (62 mph)
  • *** = Manual First-Second gear is only available above approximately 60 km/h (37 mph)
  • Manual First-Third gear is also possible at high vehicle speed as a safety feature

Circuit Description

The Powertrain Control Module (PCM) calculates gear ratio based on the transmission input and output speeds. The PCM compares the known transmission gear ratio to the calculated ratio for the selected gear range.

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

Conditions for Setting the DTC

    • No TP DTCs P0121, P0122, or P0123.
    • No VSS DTCs P0502 or P0503.
    • No A/T ISS DTCs P0716 or P0717.
    • No TFP Val. Position Sw. DTC P1810.
    • The engine is running.
    • The TFP Val. Position Sw. is not indicating Park or Neutral.
    • The transmission fluid temperature is greater than 20°C (68°F).
    • The MAP is greater than 20 kPa.
    • Engine torque is greater than 0 N·m (0 lb ft).
    • The time since the gear select lever change is greater than 6 seconds.
    • The TP is greater than 15%.
    • The vehicle speed is greater than 8 km/h (5 mph).

And one of the following conditions occurs:

    • The gear ratio is less than 1:2.87, or greater than 1:3.13, for 7 seconds.
    • The gear ratio is less than 1:1.54, or greater than 1:1.71, for 7 seconds.
    • The gear ratio is less than 1:0.91, or greater than 1:1.07, for 7 seconds.
    • The gear ratio is less than 1:0.61, or greater than 1:0.72, for 7 seconds.
    • The gear ratio is less than 1:2.02, or greater than 1:2.23, for 7 seconds.

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 from being updated.
    • DTC P0730 is stored in the PCM history.

Conditions for Clearing the DTC

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

Diagnostic Aids

    • Inspect for intermittent Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) circuit conditions.
    • Inspect for intermittent Automatic Transmission Output (Shaft) Speed Sensor (A/T OSS) circuit conditions.
    • Inspect for an incorrect calibration.

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 incorrect 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 (2.4L)

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

2

Visually inspect the transmission cooling system for fluid leaks.

Refer to Fluid Leak Diagnosis and Repair .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 3

3

Have you performed the transmission fluid checking procedure?

--

Go to Step 4

Go to Transmission Fluid Check

4

  1. Install the Scan Tool .
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. 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.

  4. Record the DTC Failure Records, then 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 greater than 15%, and the vehicle speed greater than 8 km/h (5 mph).
  7. Record each transmission gear.

Did the commanded gear ratio match the specified ranges?

Reverse: 1:2.02-1:2.23

1st: 1:2.87-1:3.13

2nd: 1:1.54-1:1.71

3rd: 1:0.91-1:1.07

4th: 1:0.61-1:0.72

Go to Diagnostic Aids

Go to Step 5

5

Perform the line pressure check.

Refer to Line Pressure Check Procedure .

Is the line pressure within specifications?

--

Go to Step 7

Go to Step 6

6

Inspect for excessive clutch wear.

Refer toClutch Plate Diagnosis .

Did you find and correct the condition?

--

Go to Step 7

--

7

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. • Drive the vehicle in D4 with the throttle greater than 15% in order to obtain any one of the following gear ratios for 7 seconds.
    • Reverse: 1:2.02-1:2.23
    • 1st: 1:2.87-1:3.13
    • 2nd: 1:1.54-1:1.71
    • 3rd: 1:0.91-1:1.07
    • 4th: 1:0.61-1:0.72
  5. Select Specific DTC. Enter DTC P0730.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to Step 1

DTC P0730 Incorrect Gear Ratio 3.1L

Table 1: Range Reference Table (For DTC P0730)
Table 2: DTC P0730 Incorrect Gear Ratio (3.1L)

Range Reference Table (For DTC P0730)

Range

Park/Neutral

Reverse

D

3

2

1

Gear

N

R

1st

2nd

3rd

4th

1st

2nd

3rd

1st

2nd

3rd**

1st

2nd***

1-2 Shift Solenoid

ON

ON

ON

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

ON

OFF

2-3 Shift Solenoid

OFF

OFF

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

ON

OFF

OFF

2nd Clutch

--

--

--

A

A*

A*

--

A

A*

--

A

A*

--

A

2nd Roller Clutch

--

--

--

H

O

--

--

H

O

--

H

O

--

H

Int./4th Band

--

--

--

--

--

A

--

--

--

--

A

--

--

A

Reverse Clutch

--

A

--

--

--

--

--

--

--

--

--

--

--

--

Coast Clutch

--

--

--

--

--

--

A

A

A

A

A

A

A

A

Input Sprag

--

--

H

H

H

O

H

H

H

H

H

H

H

H

Direct Clutch

--

--

--

--

A

A

--

--

A

--

--

A

--

--

Forward Clutch

--

--

A

A

A

A*

A

A

A

A

A

A

A

A

Lo/Rev Band

A

A

--

--

--

--

--

--

--

--

--

--

A

--

Lo Roller Clutch

--

--

H

O

O

O

H

O

O

H

O

O

H

O

  • A = Applied
  • H = Holding
  • O = Overrunning
  • ON = The solenoid is energized.
  • OFF = The solenoid is de-energized
  • * = Applied with no load
  • ** = Manual Second-Third gear is only available above approximately 100 km/h (62 mph)
  • *** = Manual First-Second gear is only available above approximately 60 km/h (37 mph)
  • Manual First-Third gear is also possible at high vehicle speed as a safety feature

Circuit Description

The Powertrain Control Module (PCM) calculates gear ratio based on the transmission input and output speeds. The PCM compares the known transmission gear ratio to the calculated ratio for the selected gear range.

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

Conditions for Setting the DTC

    • No TP DTCs P0121, P0122 or P0123.
    • No VSS DTCs P0502 or P0503.
    • No A/T ISS DTCs P0716 or P0717.
    • No TFP Val. Position Sw. DTC P1810.
    • The engine is running.
    • The TFP Val. Position Sw. is not indicating Park or Neutral.
    • The transmission fluid temperature is greater than 20°C (68°F).
    • The MAP is greater than 10 kPa.
    • Engine torque is greater than 25 N·m (20 lb ft).
    • The time since the gear select lever change is greater than 6 seconds.
    • The TP is greater than 15%.
    • The vehicle speed is greater than 8 km/h (5 mph).

And one of the following conditions occurs:

    • The gear ratio is less than 1:2.87, or greater than 1:3.13, for 7 seconds.
    • The gear ratio is less than 1:1.54, or greater than 1:1.71, for 7 seconds.
    • The gear ratio is less than 1:0.91, or greater than 1:1.07, for 7 seconds.
    • The gear ratio is less than 1:0.61, or greater than 1:0.72, for 7 seconds.
    • The gear ratio is less than 1:2.02, or greater than 1:2.23, for 7 seconds.

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 from being updated.
    • DTC P0730 is stored in the PCM history.

Conditions for Clearing the DTC

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

Diagnostic Aids

    • Inspect for intermittent Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) circuit conditions.
    • Inspect for intermittent Automatic Transmission Output (Shaft) Speed Sensor (A/T OSS) circuit conditions.
    • Inspect for an incorrect calibration.

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 incorrect 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 (3.1L)

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

2

Visually inspect the transmission cooling system for fluid leaks.

Refer to Fluid Leak Diagnosis and Repair .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 3

3

Have you performed the transmission fluid checking procedure?

--

Go to Step 4

Go to Transmission Fluid Check

4

  1. Install the Scan Tool .
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. 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.

  4. Record the DTC Failure Records, then 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 greater than 15%, and the vehicle speed greater than 8 km/h (5 mph).
  7. Record each transmission gear.

Did the commanded gear ratio match the specified ranges?

Reverse: 1:2.02-1:2.23

1st: 1:2.87-1:3.13

2nd: 1:1.54-1:1.71

3rd: 1:0.91-1:1.07

4th: 1:0.61-1:0.72

Go to Diagnostic Aids

Go to Step 5

5

Perform the line pressure check.

Refer to Line Pressure Check Procedure .

Is the line pressure within specifications?

--

Go to Step 7

Go to Step 6

6

Inspect for clutch slippage.

Refer to Transmission Diagnosis.

Did you find and correct the condition?

--

Go to Step 7

--

7

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. • Drive the vehicle in D4 with the throttle greater than 15% in order to obtain any one of the following gear ratios for 7 seconds.
    • Reverse: 1:2.02-1:2.23
    • 1st: 1:2.87-1:3.13
    • 2nd: 1:1.54-1:1.71
    • 3rd: 1:0.91-1:1.07
    • 4th: 1:0.61-1:0.72
  5. Select Specific DTC. Enter DTC P0730.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to Step 1