Inspection Procedure 12

INSPECTION PROCEDURE 12: No Diagnostic Trouble Codes (Does not Shift)






CIRCUIT OPERATION
^ PCM (terminal number 66) receives battery positive voltage from the battery.

COMMENT
^ If shifting does not occur while driving and no diagnostic trouble codes are output, a malfunction of the Park/Neutral position switch, or PCM may exist.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Malfunction of Park/Neutral position switch
^ Damaged harness, connector
^ Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
^ MB991502: Scan Tool (MUT-II)

STEP 1. Check the vehicle acceleration.
Q: Does the vehicle accelerate poorly (transmission stays in 3rd gear) when starting from a stop with the selector lever in "D" range?
YES: Go to Step 2.
NO: Go to Step 5.

STEP 2. Check the backup power supply voltage at PCM connector C-90 by backprobing.





1. Do not disconnect connector C-90.





2. Measure the voltage between terminal 66 and ground by backprobing.
^ Voltage should be battery positive voltage.
Q: Is the voltage normal?
YES: Go to Step 4.
NO: Go to Step 3.





STEP 3. Check connector C-90 at PCM for damage.
Q: Is the connector in good condition?
YES: Repair harness open circuit between PCM connector C-90 terminal 66 and fusible link.
NO: Repair or replace it. Then check for the symptom.





STEP 4. Using scan tool MB991S02, check for A/T diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Check for A/T diagnostic trouble code.
4. Turn the ignition switch to "LOCK" (OFF) position.
Q: Is the A/T diagnostic trouble code number "54" output?
YES: Refer to diagnostic trouble code number 54: A/T control relay system.
NO: Go to Step 5.





STEP 5. Using scan tool MB991502, check data list item 61: Park/Neutral Position Switch.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Set scan tool MB991502 to data reading mode for item 61: Park/Neutral Position Switch.
^ Move the selector lever to "P," "R," "N," "D," "3," "2," "L" to confirm whether the scan tool.
4. Turn the ignition switch to "LOCK" (OFF) position.
Q: Is the switch operating properly?
YES: Check for the symptom. If the symptom is not eliminated, replace the PCM.
NO: Refer to dignities trouble code number 27, 28: Park/Neutral position switch system.