Inspection Procedure 10

INSPECTION PROCEDURE 10: Early or Late Shifting in All Gears

COMMENT
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 CONDITION:)
^ 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 Tools:
^ MB991958: Scan Tool (M.U.T-III Sub Assembly)
^ MB991824: V.C.I.
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check data list item 6: 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 the data reading mode.
^ Item 6: Output Shaft Speed Sensor.
- When driving at constant speed of 50km/h (31 mph), the display should be "1,500 - 1,800 r/min" (Gear range: 3rd gear [4A/T]).
- When driving at constant speed of 60km/h (37mph), the display should be "1,400 - 1,700 r/min" (Gear range: 4th gear [5A/T]).
(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 P1767 (P0720): Output shaft speed sensor system. P1767

STEP 2. Using scan tool MB991958, check data list item 2: 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 the data reading mode.
^ Item 2: TP Sensor.
- With the throttle valve in idle position, voltage should measure between 300 and 700 mV.
- With the throttle valve in full-open position, voltage should measure 4,000 mV or more.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q : Is the measured voltage between 300 and 700 mV at idle, and 4,000 mV or more at the full-open position?
YES : Go to Step 3.
NO :Check the TP sensor. Then check the symptom.

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 the data reading mode for following items.
a. Item 12: Low-Reverse Solenoid Valve Duty Percent
b. Item 13: Underdrive Solenoid Valve Duty Percent
c. Item 14: Second Solenoid Valve Duty Percent
d. Item 15: Overdrive Solenoid Valve Duty Percent
e. Item 16: Reduction Solenoid Valve Duty Percent [5A/T]
- Check that the values shown below are displayed when each data list item is entered.

[4A/T]:

[5A/T]:

(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.
When the PCM is replaced, register the encrypted code.

Q : Is the symptom eliminated?
YES : The procedure is complete.
NO : Start over at Step 1.