I have a 1998 Pontiac Transport the SES light came on revealed a code
440 emissions problem. Replaced the gas cap, reset the ECM and the
code went out. 100 miles later the SES light came back on steady all
the time after the car cranks, even after the battery has been
disconnected it still remains on. The engines runs normal as always.
The kicker is that putting a ECM reader on the ALDC shows that there
is no power at the connector. Nothing has been modified in the car
other than replacing the stock radio with an aftermarket radio
("professionally" installed) Does the radio have an electronic
connection to the ECM or the ALDC?
Any clues appreciated...
Check pin #16 of the DLC connector for battery voltage.
If not 12 volts, check the cigar/DLC fuse (15 amp) to see if its
Check pins #4 and #5 of the DLC connector for continuity to
Pin #14 of the DLC is a serial data line to the radio but I doubt
that it would interfere with a code reader powering up off of the
Thanks, that was the fix. It was the cigar lighter fuse that is
linked to the ALDC. It was blown thanks to the jerko that installed
the radio. Never noticed that the fuse was blown cause I dont use the
lighter at all.
The code reader had a code of 440 so now it leads to a new problem...
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