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Turn key on and parking lamps and instrument panel lamps flash rapidly for one minute. Ignition relay in engine compartment fuse panel has pulsing 12 volts at the ignition 1 terminal. (relay solenoid power). Does anyone have a schematic diagram for the under hood fuse panel? I don't know the source of the b+ to the solenoid circuit.
First off welcome to the Forum !!...second, please include the year of the car with all mods either in the thread OR in your member profile...this helps us help you !!...some model years have variances in either components or in wiring !!...kind of confused what you are trying to say in your electrical troubleshooting...are you talking about ignition relay 42 ??...the P1518 (TAC Module Serial Data Circuit) will set if the battery is weak or you may see this DTC with a bad ignition switch (I did when my ignition switch was faulty)....I'd take your battery to your friendly parts store first and have it load tested...you can also do a voltage drop check between battery positive and one of the important fuses in the underhood to check for a bad switch if you are familiar with that procedure !!!
2001 Coupe, automatic trans and everything is as built. Relay is No. 42 in the engine compartment fuse panel. Battery is brand new and voltage is fully charged. Do not have a voltage drop between the battery and the fuse panel. In following the diagnostic procedures, recorded 12 volts at relay 42 B+ terminal with key on or off. Then checked ignition 1 voltage with the key on and the voltage is pulsing 12 volts. Jumpered the relay B+ pin to the load pin and all Eng Ign 1, INJR 1, and A/C circuits recorded 12 volts. Relay tested good. Issue is the 12 volts to initiate the relay is pulsing, not continuous. Need the source of this circuit to diagnose why the power is pulsing. Am afraid that it comes from the PCM and I have a faulty PCM.
I will not be able to access my '01 wiring till later tonight but if you think your PCM may be faulty a quick check is to see if you have a 5 volt ref. at the PCM with key ON...this will at least tell you if the PCM is "alive"...you can access the 5 volt ref. at the yellow wire at the MAF sensor !!...you can also check PCM power and grounds...pin outs enclosed !!
Just figuring out what you were doing...so you jumped the LOAD side of IGN Relay 42 (87 to 30) and you had a steady 12 volts but all you are seeing is "pulsing" 12 volts when not ??...the control side of the relay may be "chattering" or "buzzing" from a large voltage drop across the ignition switch and not supplying enough voltage to keep the relay contact closed...can you put your finger on the relay and feel that ??....how exactly did you do your voltage drop check "between the battery and the fuse panel"...WHERE on the fuse panel ???????????...also did you check the ground side of the relay ??..."loaded circuit testing" with an old headlight bulb is the only way to go and not a resistance check...looks like the ground side of ignition relay 42 goes into S120 (splice 120) to G120 (above the starter)..... PS- Do you hear the fuel pump prime for 2 seconds when you turn the key ON ???
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Fault Code P1518
