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2002 trans 5.7 no crank no start

by jayhatton88 on Jul 10 2017, 6:04 PM

so i had post last week about this car, cant seem to find it now. well what we have is a no crank no start another tech diagnosed it as bad starter replaced it and still nothing.. so long story short he thru parts at it bcm lock cylinder security relay ignition switch and now pn switch/ start switch and nothing. if some one can give ME an idea where to go so this weight can leave the shop i would greatly appricieate it. VIN 2g2fv22g022116189

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9 Replies

By skevindunc Sep 22 2017, 12:14 AM

Check for gps tracker with ignition kill.if the vehicle is financed through a used car dealer and late on payments the lender may have shut it down to Repo it

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By voltageviking Aug 14 2017, 2:16 PM

This comes down to having a good angle of approach and attack. Break out a wiring diagram and communication network diagram. Verify you have voltage where it's supposed to be. Start at the starter motor S-terminal while the ignition switch is in start position. If not, remove relay and check power and ground according to wiring diagram. If you are not getting a control signal to the relay from the bcm, you will need a professional scan tool to check communication pids and codes. Verify the bcm recognizes the key. If it is indeed a key/fob issue, I know that certain Snap-On scanners (I own a Modis Edge) will complete a key relearn procedure.

Hope this helps.

Also, very important to verify the starter motor is properly grounded.

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By vanislewrenches Aug 01 2017, 6:48 PM

This may be a stupid question but is the key programmed to the vehicle? Not sure what the vehicle is but if the key has a chip in it and it's not programmed to the vehicle you will get a no start/ no crank. You will have key on power but it won't do anything when you turn to start. Same thing with key fob type keys. Had a similar issue with a Chrysler 300, guy changed the BCM, TCM, and ECM and the vehicle wouldn't start with his key without programming them. Some Chrysler key fobs even need to be replaced at that point.

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By Garage Forum Admin Jul 13 2017, 4:11 PM

The first would be to get access to a scan tool ( it needs to be a “professional” scan tool) not a code reader. Then make sure that the PCM and the BCM are communicating. The PCM (Powertrain Control Module) tells the BCM (Body Control Module) to supply ground for the starter relay. Using the scan tool you can command the relay to close to verify the BCM has the ability to drive the relay to ground. This will also test all the other components on the control side. If the vehicle starts and runs then you know all the new parts that have been replaced are working. If it cranks with the scanner output command, follow the wiring diagram to see why the ignition key crank signal is not being recognized by the PCM. You can monitor the input from the ignition switch to the PCM on the data list to verify the input.

Of course, this is assuming you've verified there are no DTC’s in either the PCM or BCM, which would then be the starting point for diagnosis.

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By jeffreyd1 Jul 12 2017, 2:50 PM

So are you losing power to Relay pin 85 or ground to Relay pin 86? You have to know this. Once you get that, we can continue testing.

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By jayhatton88 Jul 11 2017, 1:17 PM

it will start and run when jumping the starter relay.

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By jeffreyd1 Jul 11 2017, 1:08 AM

Go to the starter relay. You should have battery power at all times on Pin 30. If not, check 50A ignition Maxi Fuse or wiring to Relay. Check for ignition switch start position power to Pin 85. If that is missing, check for loss of voltage through p/n switch, ignition switch, wiring, or blown 15A starter fuse. If that is good, Check for ground on Pin 86. If no ground when cranking, check for BCM problem(including security malfunction). If those are all good. jumper between pin 30 & 87 to see if the starter will crank. If it will not, check starter solenoids, or wiring to starter. Let us know which way the problem is & we'll work backwards with you from there.

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By jayhatton88 Jul 10 2017, 7:11 PM

relearn as in with the key on till light stops flashing? we have done that.. but if there is another procedure what would that be?

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By qualityservice Jul 10 2017, 6:52 PM

Do a relearn procedure

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