98 Pontiac Transport SES Light steady on, NO POWER AT THE ALDC !!??

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...

Reply to
Cybershooter
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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 blown.

Check pins #4 and #5 of the DLC connector for continuity to ground.

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 DLC.

Reply to
Neil Nelson

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...

Reply to
Cybershooter

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