Cherokee XJ 97 RHD ASD Electrical Issues
#1
Cherokee XJ 97 RHD ASD Electrical Issues
A big hello from Australia
I hope all is well where ever you are. I'm an avid fixit guy who keeps finding old cars looking for a new home. This has been an ongoing hobby for me fixing cars and bring them it back to life. I've picked up a tired Cherokee XJ 97 limited. I'm learning something new all the time. The beast wasn't going when I got it but new with a bit of time patience it will. The harmonic balance had completely come off so I replaced it and the timing chain and front crank seal. First test crank but no start. The red GEN light isn't coming on and cant get any a orange engine fault either to light up either(power?). No codes when plugging in the ODBC. Did the obvious stuff relays and fuses all ok. Replaced the CPS (new) no change. Ok now comes the technical questions. I've gone through all the wiring diagrams to isolate what I think it maybe. I've also checked the forum and its
helped to get to this point so far.
All other electrics work fine when key is ignition mode lights etc etc.
- The fuel pump wont start when key is in ignition, when I bypass it at the relay it works
-FPR is new
-ASD relay is new
-Traced all wires back to PCM
-All wires from PCM to relay are all ok did a continuity with multimeter and circuit test light to check for broken wires.
-When I check A7 pin out on the PCM no response (ignition coil) - ignition on
-When I check C3 pin out on the PCM no response (ASD) - ignition on
-I checked the coil no spark (New coil just in case) checked the ohms as well all within spec
-Checked NSS all good.
Does anyone know why the A7 and C3 not sending its grounding signal to the relays?
Dead ECU?
Many thanks in advance to the knowledge room
Regards Aussie_Guy
I hope all is well where ever you are. I'm an avid fixit guy who keeps finding old cars looking for a new home. This has been an ongoing hobby for me fixing cars and bring them it back to life. I've picked up a tired Cherokee XJ 97 limited. I'm learning something new all the time. The beast wasn't going when I got it but new with a bit of time patience it will. The harmonic balance had completely come off so I replaced it and the timing chain and front crank seal. First test crank but no start. The red GEN light isn't coming on and cant get any a orange engine fault either to light up either(power?). No codes when plugging in the ODBC. Did the obvious stuff relays and fuses all ok. Replaced the CPS (new) no change. Ok now comes the technical questions. I've gone through all the wiring diagrams to isolate what I think it maybe. I've also checked the forum and its
helped to get to this point so far.
All other electrics work fine when key is ignition mode lights etc etc.
- The fuel pump wont start when key is in ignition, when I bypass it at the relay it works
-FPR is new
-ASD relay is new
-Traced all wires back to PCM
-All wires from PCM to relay are all ok did a continuity with multimeter and circuit test light to check for broken wires.
-When I check A7 pin out on the PCM no response (ignition coil) - ignition on
-When I check C3 pin out on the PCM no response (ASD) - ignition on
-I checked the coil no spark (New coil just in case) checked the ohms as well all within spec
-Checked NSS all good.
Does anyone know why the A7 and C3 not sending its grounding signal to the relays?
Dead ECU?
Many thanks in advance to the knowledge room
Regards Aussie_Guy
Last edited by Aussie_Guy; 08-24-2021 at 06:53 AM.
#3
I believe the Australian '97 model apparently has a unique to that year immobiliser system.
'96 and earlier had none, '98 and later have a different immobiliser
there is an Aussie forum where this matter has been discussed, however, I do not recall anyone having been definitely able to overcome this issue
'96 and earlier had none, '98 and later have a different immobiliser
there is an Aussie forum where this matter has been discussed, however, I do not recall anyone having been definitely able to overcome this issue
#4
Thanks AWG and DJ. AWG is there a relay for the immobiliser? My truck is fitted with an aftermarket unit and disabled it. I thought the same thing. I even traced the power wire back from the ignition key to the fuse box with the relays under the bonnet. I'm getting power to that point. Ill check the grounding on the coil. Thanks Guys
#5
one guy told me he fixed a dead '97 by replacing the PCM, I dont know a lot about the immobiliser, but I think it sends a signal via a "skim" module
free download and have a read of the '97 manual, as the ASD relay has to get all its signals and operate, in order for the fuel pump relay to operate
As I understand it, failure of the immobiliser means the fuel pump will shut off after 3 secs (so it will actually start)
I could be wrong
on my 96, the fuel pump runs for 3 secs when you turn the ignition to the full accesory position
free download and have a read of the '97 manual, as the ASD relay has to get all its signals and operate, in order for the fuel pump relay to operate
As I understand it, failure of the immobiliser means the fuel pump will shut off after 3 secs (so it will actually start)
I could be wrong
on my 96, the fuel pump runs for 3 secs when you turn the ignition to the full accesory position
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