Inspection Procedure 10
INSPECTION PROCEDURE 10: Early or Late Shifting All GearsCOMMENT
If all shift points are early or late while driving, the cause is probably a malfunction of the output shaft speed sensor, TP sensor or a solenoid valve.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Malfunction of the output shaft speed sensor
^ Malfunction of the TP sensor
^ Malfunction of each solenoid valve
^ Abnormal line pressure
^ Malfunction of the valve body
^ Malfunction of the PCM
DIAGNOSIS
Required Special Tool:
^ MB991958: Scan Tool (MUT-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: MUT-III USB Cable
^ MB991911: MUT-III Main Harness B
STEP 1. Using scan tool MB991958, check data list item 23: Output Shaft Speed Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1) Connect scan tool MB991958 to the data link connector.
2) Start the engine.
3) Set scan tool MB991958 to data reading mode for item 23: Output Shaft Speed Sensor.
^ 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>. (Gear range: 3rd gear)
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 2.
NO: Refer to DTC 23: Output shaft speed sensor system.
STEP 2. Using scan tool MB991958, check data list item 11: TP Sensor.
1) Connect scan tool MB991958 to the data link connector.
2) Turn the ignition switch to the "ON" position.
3) Set scan tool MB991958 to data reading mode for item 11: TP Sensor.
^ With the throttle valve in idle position, voltage should measure between 535 and 735 mV.
^ With the throttle valve in full-open position, voltage should measure between 4,500 and 5,500 mV.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 535 and 735 mV at idle, and between 4,500 and 5,500 mV in the full-open position?
YES: Go to Step 3.
NO: Check the TP sensor. Then check the malfunction.
STEP 3. Using scan tool MB991958, check data list.
1) Connect scan tool MB991958 to the data link connector.
2) Start the engine.
3) Set scan tool MB991958 to data reading mode for following items.
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
^ Check that the values shown are displayed when each data list item is entered.
4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are the solenoid valves operating properly?
YES: Go to Step 4.
NO: Go to Step 6.
STEP 4. Adjust the line pressure. Adjust the line pressure.
Refer to Line Pressure Adjustment. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 5.
STEP 5. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve body for damage. Repair or replace the faulty parts. Replace the valve body assembly if the damages are thought to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 7.
STEP 6. Replace each solenoid valve.
Replace the faulty solenoid valve with a new one.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 7.
STEP 7. Replace the PCM.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Start over at Step 1.