Starting - Dead Battery/No Crank After Overnight Set

BulletinNo. T 85-36
File In Group 6D
Number 22
Date Dec. '84
SUBJECT: DISCHARGED BATTERY OR NO CRANK AFTER OVERNIGHT SET

MODELS AFFECTED: 1981-1985 DEVILLE (RWD), BROUGHAM, ELDORADO AND SEVILLE 1985 FWD DEVILLE AND FLEETWOOD


A battery drain may be experienced on some 1981-1985 DFI equipped vehicles as a result of the Electronic Control Module (ECM) not powering down with the ignition switch off. This can be diagnosed as follows:


1. Turn ignition on, enter diagnostics.

2. Note ECM parameter .0.9 "Ignition Cycles."

3. Turn ignition off for at least 10 seconds to allow ECM to power down.

4. Turn ignition on, re-enter diagnostics and note ECM parameter .0.9.

The ignition cycle counter should increment by one. If this does not occur and no "hard" trouble codes are present, the ECM is unable to power down and must be replaced. The failure of the ECM to power down can also be determined by observing the five-volt reference at the TPS test point with the ignition off. If the five-volt reference remains at 5 volts after the ignition has been off for 10 seconds, the ECM should be replaced.

Should the ignition cycle counter increase by one, the battery drain must be diagnosed using the procedure provided in the "Engine Electrical" section of the appropriate Service Information Manual.