Inspection Procedure 10
INSPECTION PROCEDURE 10: All points (Early or late shift points)COMMENT
If all shift points are early or late while driving, the cause is probably a malfunction of the output shaft speed sensor, throttle position sensor or a solenoid valve.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set:)
- Malfunction of the output shaft speed sensor
- Malfunction of the throttle position sensor
- Malfunction of each solenoid valve
- Abnormal line pressure
- Malfunction of the valve body
- Malfunction of the PCM
DIAGNOSIS
REQUIRED SPECIAL TOOL:
- MB991502: Scan Tool (MUT-II)
CAUTION: To prevent damage to the scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting the scan tool MB991502.
STEP 1. Using scan tool MB991502, check data list item 23: Output shaft speed sensor.
1) Connect scan tool MB991502 to the data link connector.
2) Set scan tool MB991502 to the data reading mode for item 23, Output shaft speed sensor.
3) Start the engine. Move the selector lever to "3"
4) When driving at constant speed of 50 km/h (31 mph), the display should be 1,600 - 1,900 r/min <2.4L Engine>, 1,300 - 1,600 r/min <3.0L Engine>.
Q: Is the result of the above check good (Is the output shaft speed sensor operating properly)?
YES: Go to Step 2.
NO: Refer to Code number 23 - Output shaft speed sensor system.
STEP 2. Using scan tool MB991502, check data list item 11: Throttle position sensor.
1) Set scan tool MB991502 to the data reading mode for item 11, Throttle position sensor.
2) When the accelerator pedal is not depressed (throttle valve is fully closed), the display should be "535 to 735 mV."
3) When the accelerator pedal is depressed, the display should gradually rise.
4) When the accelerator pedal is fully depressed (throttle valve is fully open) (up to two seconds), the display should be "4,500 to 5,500 mV.'
Q: Is the result of the above check good (Is the throttle position sensor operating properly?
YES: Go to Step 3.
NO: Check the throttle position sensor. Then check the malfunction.
STEP 3. Using scan tool IUIB991502, check data list.
1) Check the following items in the data list.
a. Item 31: Low-reverse solenoid valve duty percent
b. Item 32: Underdrive solenoid valve duty percent
c. Item 33: Second solenoid valve duty percent
d. Item 34: Overdrive solenoid valve duty percent
2) Check that the values shown below are displayed when each data list item is entered.
Q: Is each solenoid valve duty percent within specifications?
YES: Go to Step 4.
NO: Go to Step 6.
STEP 4. Adjust the line pressure.
1) Adjust the line pressure. Then check the symptom.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 5.
STEP 5. Disassemble and clean the valve body.
1) Check the O-ring installation bolts for looseness and the valve body for damage. Repair or replace the faulty parts.
Q: Is the repair possible and the symptom eliminated?
YES: Diagnosis is complete.
NO: Replace the valve body assembly. Then check the symptom. Go to Step 7.
STEP 6. Replace each solenoid valve.
1) Replace the faulty solenoid valve with a new one.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 7.
STEP 7. Replace the PCM.
1) Replace the PCM. The immobilizer-ECU and the ignition key should be replaced together with it. Confirm that the malfunction symptom is eliminated.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.