No Start Issue - 2001 Aurora 3.5

[atentaten]

2001 Aurora 3.5.
I recently replaced the ignition switch with help from folks on this forum.
However, my no start issue is the still the same. The problem is:

I noticed that the under hood ignition relay no longer clicks when turning the ignition switch in the run position and verified that the relay is good.
The 10 amp ignition fuse under the hood never gets power even when the switch in the run or start position.

Any ideas what could be causing this?

Thanks!

[AuroraGirlFromMars]

Nov 22, 2022 19:58:46 GMT -6 atentaten said:

2001 Aurora 3.5.
I recently replaced the ignition switch with help from folks on this forum.
However, my no start issue is the still the same. The problem is:

I noticed that the under hood ignition relay no longer clicks when turning the ignition switch in the run position and verified that the relay is good.
The 10 amp ignition fuse under the hood never gets power even when the switch in the run or start position.

Any ideas what could be causing this?

Thanks!

STOP THROWING PARTS AT IT AND TRY DOING SOME DIAGNOSTICS

you replaced the IGNITION SWITCH?  So if you are syaing you did not replace your iginition tumblr, then Im not sure about your issue., bu

[Marc]

Nov 23, 2022 17:23:24 GMT -6 AuroraGirlFromMars said:

Nov 22, 2022 19:58:46 GMT -6 atentaten said:

2001 Aurora 3.5.
I recently replaced the ignition switch with help from folks on this forum.
However, my no start issue is the still the same. The problem is:

I noticed that the under hood ignition relay no longer clicks when turning the ignition switch in the run position and verified that the relay is good.
The 10 amp ignition fuse under the hood never gets power even when the switch in the run or start position.

Any ideas what could be causing this?

Thanks!

STOP THROWING PARTS AT IT AND TRY DOING SOME DIAGNOSTICS

you replaced the IGNITION SWITCH?  So if you are syaing you did not replace your iginition tumblr, then Im not sure about your issue., bu

Have it scanned. Guesswork on an Aurora is next to impossible.

[paulaurora]

3.5 common issue is the starter as well . Make sure that starter is good.

[atentaten]

Thanks for the suggestions. I've narrowed the problem down to the following:

Context: Starter relay (start 1) will not actuate in its fusebox socket when ignition is turned.

• Known good relays will not actuate in the start 1 socket
  
• Tested that power is getting to the relay by inserting leads into the proper socket portals and reading via volt meter and light lead tester and turning ignition switch.
• The relay will actuate with the default hot while using a different ground than the one in the fusebox socket!

It seems that there may be an issue with the wire that goes from the PCM to the start1 relay socket or the PCM.
The PCM is supposed to ground the circuit through that wire. I don't know if there is a problem with the wire or with the PCM.

Bottom line:
Even though power is getting through to the relay, it seems that the ground is not allowing sufficient amps to actuate it. Using another ground does actuate the relay.
Does anyone have any comments or suggestion related to this issue?

Thanks

 

[quixote]

This may be totally out of left field, from the Resident Idiot (Me)... but on the 4.0, the alternator has a fine wire (maybe 16ga??) ground that loops up a little bit. Mine was broken my accident, when I had a shop replace my starter. On the 4.0 the intake manifold has to be removed, to replace the starter, & you have to take care with that wire.

I don't think the 3.5 has even similar starter/intake, but it's worth looking for that alternator wire... All I did to fix the issue (which was lights on, but 0 from the engine compartment, at "start,") ---was strip the two wire-ends and put a wire-nut on it.

As I say, I don't know the 3.5, so I may be way off. I don't know if the wire on mine is part of the harness, or comes off of the alternator... I just know that it's far too easy & cheap a fix to not take a look, make sure your wires are all okay.

Good luck

[AuroraGirlFromMars]

sounds like your PCM is inhibiting start, probably due to something like passkey 3 intervention or an issue with Park-Neutral detection (scan tool can help with this)

[quixote]

...It just occurred to me: is your anti-theft module working??

I'm trying to remember exactly how the one in the Aurora works, but I know they can fail completely & the only things that will get your car to start --if it does-- are replacement or complete bypass. I've never done it, but the steps to bypass are here in the Forum, somewhere.

I had to re-read this thread, to confirm that no one had already suggested the anti-theft. To my mind, I should be high on the list of possibilities. I only have personal experience with two different GM models that use this generation on the anti-theft. (The other being a 1996 Pontiac, bought new.) The module on that Pontiac failed out of nowhere, when it was 2-3 years old.

Sorry, I don't even know if this would come up on an OBDII scan? I guess the easiest way to check it, beside maybe OBDII, would be for you to try a different [known good] key.

[AuroraGirlFromMars]

Dec 28, 2022 1:11:53 GMT -6 quixote said:

...It just occurred to me: is your anti-theft module working??

I'm trying to remember exactly how the one in the Aurora works, but I know they can fail completely & the only things that will get your car to start --if it does-- are replacement or complete bypass. I've never done it, but the steps to bypass are here in the Forum, somewhere.

I had to re-read this thread, to confirm that no one had already suggested the anti-theft. To my mind, I should be high on the list of possibilities. I only have personal experience with two different GM models that use this generation on the anti-theft. (The other being a 1996 Pontiac, bought new.) The module on that Pontiac failed out of nowhere, when it was 2-3 years old.

Sorry, I don't even know if this would come up on an OBDII scan? I guess the easiest way to check it, beside maybe OBDII, would be for you to try a different [known good] key.

well I just did bring it up 12 hours ago  

that 1996 pontiac did not use this antitheft.   The earliest that these platform cars/neighbor platforms had the same system was 1997 with the buick park avenue

its called passkey 3
it wont come up for a basic scanenr but it there are codes/diagnostics to be seen on the car through that port. if you have the tool

[atentaten]

>>...It just occurred to me: is your anti-theft module working??

>> sounds like your PCM is inhibiting start, probably due to something like passkey 3 intervention or an issue with Park-Neutral detection (scan tool can help with this)

I've thought about a possible security issue, but I have no lights on the dash indicating it. Also, no trouble codes coming out of two different ODBII readers. Maybe they need to be more sophisticated?

It's a weird because I can read 12V at the relay when the ignition switch is in start/run. I would think that if the PCM was not grounding the circuit, then there would be zero volts there. This is why I think there may be an amperage drop caused by a bad wire or some grounding problem.

[atentaten]

I've confirmed a voltage drop across the the Start 1 relay. 12V is read initially, but with a load voltage drops to essentially 11V when the ignition is in start/run. The YEL 76 ground wire from the relay to PCM is good in terms of being able to handle load when tested outside of the PCM. So it seems that there could be a problem in the PCM or maybe how the PCM is getting its ground?

[atentaten]

Just found out that I'm no longer getting full power on YEL 23 (Crank Voltage) at the PCM when the ignition is in the start/run. Was getting 12V, now getting 0.5V
The problem is morphing...

[AuroraGirlFromMars]

Dec 31, 2022 19:04:16 GMT -6 atentaten said:

Just found out that I'm no longer getting full power on YEL 23 (Crank Voltage) at the PCM when the ignition is in the start/run. Was getting 12V, now getting 0.5V
The problem is morphing...

sounds like BCM or ignition switch(power modes are switches by ignition switch  but those power modes do the heavy lifting)        also check your relays by replacing wiith similar 

[quixote]

Dec 30, 2022 19:47:13 GMT -6 atentaten said:

I've confirmed a voltage drop across the the Start 1 relay. 12V is read initially, but with a load voltage drops to essentially 11V when the ignition is in start/run. The YEL 76 ground wire from the relay to PCM is good in terms of being able to handle load when tested outside of the PCM. So it seems that there could be a problem in the PCM or maybe how the PCM is getting its ground?

I'm glad to see you have eliminated the anti-theft as your issue.

...for future (possible) reference, the '97, there was nothing to indicate anti-theft failure.  The Christmast tree lights up, then goes out.  The Anti-theft label on the dash below (or above?) the radio, continued flashing.  Normal driving condition was solid light, I think. 

And anybody who feels like updating for the differences to your specific model year, can.  I kinda feel like you don't see anything like the indicators of the module failing, until it fails, however. 

It's also entirely possible that I remember the Condition of a car from 25 years ago, wrong, like mis-remembering wether it was a 1996 or 1997.  It's why I call it "anti-theft," instead of using a trademarked acronym that could have changed five times in the intervening period.

[atentaten]

Thanks for everyone for helping with this issue.
I Just wanted to add an update to this issue.

Initially while working through this problem,  I was getting no indication of  a theft deterrent security issue (no lights, no codes).
Recently I got the security light on the dash. It blinks and stays on. Again this was not happening before.
I was able to get a tech II emulator and saw a DTC code P1626 - Theft Deterrent Fuel Enable Signal Lost.
I was getting no DTC codes with a standard ODBII code reader, but got something with the Tech II.

Anyway, when attempting to run diagnostics on the Theft Deterrent Module via the Tech II, I get communication error. 
I can run diagnostics on other systems of the vehicle via the Tech II scanner. 

I'm thinking that there could be an issue with the Theft Deterrent Module (TDM) since I cannot communicate with it. 

I'm creating a new post for continuity, and to focus on theft deterrent module since this has been an meandering problem:
aurorah.proboards.com/thread/32374/bypassing-replacing-theft-deterrent-module

[paulaurora]

Did you try to check the fuses and wires that might be damaged or corroded ?