Code No. P1637: Malfunction of Memory Backup


DIAGNOSTIC FUNCTION


The CVT-ECU determines that the system is defective if the calculated value does not correspond with the stored value.

JUDGEMENT CRITERIA


The memory backup malfunction is detected.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code
Check whether a diagnosis code other than P1637 is set.

Q. Is diagnosis code set?
Carry out the appropriate troubleshooting.
Go to Step 2

STEP 2. Check for open circuit or short to earth in BATT, BAT2 line between the CVT-ECU connector and the battery

Q. Is the check result normal?
Replace the CVT-ECU.
Repair the connector(s) or wiring harness.