Turn key to start, no “click” or noise from starter. Dash lights dim when in “start” position, headlights do not dim. Starter was replaced a few months ago, pulled it off the vehicle and bench tested it… works great. Put starter back on, ran jumper from battery to starter solenoid, starter cranks fine. Vehicle starts and
dies, turn key off and back on to cycle the fuel pump, vehicle starts and dies again. Starter is not the problem.
Using my 2003 GM express van service manual set, I started tracing voltage. When key is in “start” position, I have 12 volts running from ignition switch through the fuse block (fuse 27) to the PCM (connector C2 pin 59). This is known as the “crank” circuit. It is working correctly. The PCM knows I’m trying to start the vehicle.
Next I checked the neutral safety switch circuit that feeds the starter relay. I have 12 volts through the switch, to the coil side of the starter relay (terminal 85), then it feeds through the coil (terminal 86) and shows up at the PCM (connector C1 pin 39) as 12 volts. The PCM knows the vehicle is in park/neutral.
Next I bench tested the starter relay, worked correctly so I checked to make sure I had 12 volts on the supply side of the contacts (terminal 30). Voltage is there ready to go to starter solenoid.
Service manual says if I have start voltage at PCM (connector C2 pin 59), and voltage at PCM (connector c1 pin 39), and won’t crank… to replace PCM.
Replaced PCM, programmed to my VIN. Went through the security re-learn procedure, no issues, security light on dash now off. Still won’t turn over. No change when trying, dash lights still dim, no security light at all. Pulled DTC codes, came back P0315 crank position sensor needing a re-learn. This code won’t keep the starter from working will it? The info I have for a crank position sensor re-learn has the engine running.
All voltages have been checked more than once. Any thoughts on why I can’t get this vehicle to crank over? thanks…
You have Power at PCM (connector C2 pin 59), and voltage at PCM (connector c1 pin 39). this is good. Power comes in to the PCM on C2, the PCM says OK and sends a power signal OUT on C1 that goes to and energizes the Starter Relay. The starter relay Connects and Uses the power it obtains from IGN A Fuse 40Amp and sends it to the “S” terminal on the starter.
So when you hold the key in the “Start” position, do you see battery voltage at the “S” terminal?
Check the IGN A 40amp fuse, if it is good. Check the make sure you have power on this fuse. If not there is an inline fusible link (B) that may also be blown.
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