Inspection Procedure 3
INSPECTION PROCEDURE 3: Does not move backwardCOMMENT
If the vehicle does not backward when the selector lever is shifted from "N" to "R" range while the engine is idling, the cause is probably abnormal pressure or a malfunction of the reverse clutch, low-reverse brake, or valve body.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Abnormal reverse clutch pressure
- Abnormal low-reverse brake pressure
- Malfunction of the low-reverse solenoid valve
- Malfunction of the reverse clutch
- Malfunction of the low-reverse brake
- 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, carry out the actuator test.
1) Connect scan tool MB991502 to the data link connector.
2) Check the following item in the actuator test. a. Item 1: Low reverse solenoid valve
3) Check that the solenoid valve clicks.
NOTE: The engine must not be running for this test.
Q: Does the solenoid click?
YES: Go to Step 2.
NO: confirm the PCM is operating the solenoid by checking voltages at PCM terminal 129, connector C 61 <2.4L Engine> or C-63 <3.0L Engine. If operating properly, replace the low-reverse solenoid valve. Then confirm that the symptom is eliminated.
STEP 2. Check the hydraulic pressure (for reverse clutch).
1) Measure the hydraulic pressure for reverse clutch when the selector lever is at the "R" range, and check if the hydraulic pressure is within the standard value.
Q: Is the hydraulic pressure within the standard value?
YES: Go to Step 3.
NO: Go to Step 5.
STEP 3. Check the hydraulic pressure (for low-reverse brake).
1) Measure the hydraulic pressure for low-reverse brake when the selector lever is at the "R" range, and check if the hydraulic pressure is within the standard value.
Q: Is the hydraulic pressure within the standard value?
YES: Go to Step 4.
NO: Go to Step 5.
STEP 4. Check the reverse clutch system and low-reverse brake system.
1) Remove the valve body cover and valve body.
2) Blow compressed air into the reverse clutch oil orifice of the transaxle case. Then check if the reverse clutch piston moves and air pressures are maintained in that condition. Repeat for the low-reverse brake.
Q: Are both air pressures maintained?
YES: Go to Step 5.
NO: Go to Step 6.
STEP 5. Disassemble and clean the valve body.
1) Check the O-ring installation bolts for looseness and valve body for damage. Repair or replace the faulty parts.
Q: Is the repair possible and the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 7.
STEP 6. Check the reverse clutch and low-reverse brake. Remove the transaxle.
1) Check the facing for seizure and the piston seal ring for damage and interference with the retainer. Repair or replace the faulty parts. Then check the symptom.
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.