1997 Bravada No Start, No Spark Issue
#11
That's plenty good. By those results it confirms the PCM is able to receive the pulse through the yellow wire. Where/how did you come up with the .6 ohm reading on the purple wire?
What about this: First test makes sure the sensor is getting voltage and ground. From your previous test, it probably is, but check it anyway. Disconnect the CKP connector. Ignition in the RUN position. Check voltage from the purple wire to the pink wire. Must be battery voltage. NOTE: The purple wire is NOT the same as vehicle ground, so it must be tested at the connector.
What about this: First test makes sure the sensor is getting voltage and ground. From your previous test, it probably is, but check it anyway. Disconnect the CKP connector. Ignition in the RUN position. Check voltage from the purple wire to the pink wire. Must be battery voltage. NOTE: The purple wire is NOT the same as vehicle ground, so it must be tested at the connector.
Last edited by Captain Hook; 12-31-2014 at 03:20 PM.
#12
That schematic shows up fine. Couple problems with it though: #1 the CKP sensor is NOT a Hall effect switch. A Hall effect switch has a transmitter and a receiver. The CMP sensor is a Hall effect switch. #2 The purple wire is the ground for the sensor, yellow is the signal.
#13
Post #9 I checked the voltage between the pink and purple wires and they were battery voltage.
Purple wire to pin 28 is were I had .6 ohms
I also switched the pcm back to the one that was in it when i picked the bravada up.
I have no ground pulse on the white wire at the ICM plug.
EDIT: In post #9 I had my wire colors mixed up and you must have saw it before got it changed.
Purple wire to pin 28 is were I had .6 ohms
I also switched the pcm back to the one that was in it when i picked the bravada up.
I have no ground pulse on the white wire at the ICM plug.
EDIT: In post #9 I had my wire colors mixed up and you must have saw it before got it changed.
Last edited by hubert hefner; 12-31-2014 at 03:54 PM.
#14
I have no ground pulse on the white wire to the ICM with either PCM. I'm pretty sure that the toner ring is in there because when I put my magnet in the hole my magnet stopped about at the end of the hole. Then I stuck my finger in the hole and it feels like its in there. I could feel both side edges of the toner ring with my finger nail. Not to sound like a moron or anything but it doesn't have a fuse box under the hood.
#15
Sorry, my bad on the under hood fuse panel. You're right, not one there! Started in 1998. Yours has instrument panel only.
Still no pulse at the ICM: We're not done checking the CKP circuits, and haven't found or fixed anything, so that makes sense. Read post #11 again.
EDIT: Nevermind, you edited post #9. But I'm still curious about the .6 ohms on the purple wire
Still no pulse at the ICM: We're not done checking the CKP circuits, and haven't found or fixed anything, so that makes sense. Read post #11 again.
EDIT: Nevermind, you edited post #9. But I'm still curious about the .6 ohms on the purple wire
Last edited by Captain Hook; 12-31-2014 at 04:24 PM.
#16
That's plenty good. By those results it confirms the PCM is able to receive the pulse through the yellow wire. Where/how did you come up with the .6 ohm reading on the purple wire?
What about this: First test makes sure the sensor is getting voltage and ground. From your previous test, it probably is, but check it anyway. Disconnect the CKP connector. Ignition in the RUN position. Check voltage from the purple wire to the pink wire. Must be battery voltage. NOTE: The purple wire is NOT the same as vehicle ground, so it must be tested at the connector.
What about this: First test makes sure the sensor is getting voltage and ground. From your previous test, it probably is, but check it anyway. Disconnect the CKP connector. Ignition in the RUN position. Check voltage from the purple wire to the pink wire. Must be battery voltage. NOTE: The purple wire is NOT the same as vehicle ground, so it must be tested at the connector.
I checked the voltage at the CKP sensor from the pink wire to the purple wire via the connecter(unplugged). I tested the voltage with the ignition in the run position. Voltage at CKP connector was Battery voltage.
#17
Good, got it. Time out.... all 3 circuits at the CKP are good, and we can pretty much rule out the PCM as the problem, (not 100% though) cuz neither one works, (last guy may have fried them, who knows). Without being able to test the CKP duty cycle to get a difinitive answer, we're gonna do a work around and see if the ICM can receive the pulse from the PCM.
Haul out the ohm meter again...
Ignition OFF.
Disconnect the ignition coil & ignition module connectors.
Disconnect connector 3 at the PCM. Sorry, not sure what color 3 is, so you'll have to go hunting. Pin #9 is a white wire, (no tracer on it, just plain old white).
Check resistance from pin #9 to the white wire in the ignition module connector. Must be 5 ohms or less.
Haul out the ohm meter again...
Ignition OFF.
Disconnect the ignition coil & ignition module connectors.
Disconnect connector 3 at the PCM. Sorry, not sure what color 3 is, so you'll have to go hunting. Pin #9 is a white wire, (no tracer on it, just plain old white).
Check resistance from pin #9 to the white wire in the ignition module connector. Must be 5 ohms or less.
#18
Ok
With the coil connector unplugged and the control module connector unplugged the white wire on the control module connector to pin 9 on the #3 connector on the pcm (which is the white connector) is .3 ohms.
And by the way thank you very much for all the help so far!
With the coil connector unplugged and the control module connector unplugged the white wire on the control module connector to pin 9 on the #3 connector on the pcm (which is the white connector) is .3 ohms.
And by the way thank you very much for all the help so far!
#20
Good job. Does the "business end" of the CKP sensor show any signs of anything coming in contact with it, such as the tone ring? Either way, at this point we need to punt. Here's the logic: Neither PCM can send a pulse to the module, which could be coincidence but, we KNOW the CKP sensor has been "fooled" with and possibly damaged. I hate guessing, but at this point we don't have an option, but it's at least an educated guess.... try replacing the CKP sensor.
Last edited by Captain Hook; 12-31-2014 at 05:26 PM.