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'89 Check Eng on but no codes
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
'89 Check Eng on but no codes
Had a code 14, coolant temp sensor, replace & confirmed no shorts/open in circuit 410 (yellow) and 452 (black) to the sensor. So swapped out ECM from Oreilly, now check eng stays on & no codes...
Anyone ever seen that? We are going to exchange the ECM again this afternoon but in the mean time will confirm no short to ground in circuit 419 (brown/white) that runs the light from ECM to DIC.
FSM has NO diagnostics for Light on & no codes that I could find...
TIA.
Anyone ever seen that? We are going to exchange the ECM again this afternoon but in the mean time will confirm no short to ground in circuit 419 (brown/white) that runs the light from ECM to DIC.
FSM has NO diagnostics for Light on & no codes that I could find...
TIA.
Team Owner
Joined: Jan 2003
Posts: 20,324
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From: Summerland B.C. Canada
Instructor
Joined: Sep 2005
Posts: 135
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Had a code 14, coolant temp sensor, replace & confirmed no shorts/open in circuit 410 (yellow) and 452 (black) to the sensor. So swapped out ECM from Oreilly, now check eng stays on & no codes...
If you had no problem with the ECM but replaced it anyways, you probably have the new ECM not fully connected or dirty contacts, I'd clean them and make sure you get that nice 'snap' sound when you connect up the ECM cables.
It could be the ECM of course, but more likely something you did or dirt got in there.
I replaced my ECM on my '89 at 100k miles since my ave/instant miles readout wasn't working - after over 20 years, its nice to have that fixed.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
update
Morning, time for an update... okay, ECM was replaced due to a code 14, faulty coolant sensor. Which I helped this friend diagnose. We replaced the sensor & I ran all the tests on the wiring back to the ECM & 14 would not go away. FSM listed faulty ECM. So I had him replace.
14 is gone but then he starts calling me with this no codes but light still on... I walk him through a few things over the phone & he keeps saying no codes...
Late yesterday he shows up at my shop & says, still on, I pull codes, 12x3 & then it starts to throw a new #, he starts to say, see no codes... duh. code 33! (imho it was prob. doing that the whole time?)
So, run the diagnostics from the FSM, all the tests pass just fine... clear code several times over the tests & it comes back about 25 seconds after start. He has already replaced the MAF, both relays & I helped check some of the wiring... I also reset the TPS which was a little low. A few threads on here suggested checking base idle but they had to do with modified setups and/or larger TBs.
He has ordered a new MAF from local parts place but I'm not sure that will stop it. I'm going to suggest he check the wiring back towards the main harness with a fine tooth comb...
Anyone else have any suggestions?
14 is gone but then he starts calling me with this no codes but light still on... I walk him through a few things over the phone & he keeps saying no codes...
Late yesterday he shows up at my shop & says, still on, I pull codes, 12x3 & then it starts to throw a new #, he starts to say, see no codes... duh. code 33! (imho it was prob. doing that the whole time?)
So, run the diagnostics from the FSM, all the tests pass just fine... clear code several times over the tests & it comes back about 25 seconds after start. He has already replaced the MAF, both relays & I helped check some of the wiring... I also reset the TPS which was a little low. A few threads on here suggested checking base idle but they had to do with modified setups and/or larger TBs.
He has ordered a new MAF from local parts place but I'm not sure that will stop it. I'm going to suggest he check the wiring back towards the main harness with a fine tooth comb...
Anyone else have any suggestions?
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Verdad Gallardo
Safety Car
Joined: Jan 2014
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From: Poughkeepsie New York
Morning, time for an update... okay, ECM was replaced due to a code 14, faulty coolant sensor. Which I helped this friend diagnose. We replaced the sensor & I ran all the tests on the wiring back to the ECM & 14 would not go away. FSM listed faulty ECM. So I had him replace. 14 is gone but then he starts calling me with this no codes but light still on... I walk him through a few things over the phone & he keeps saying no codes... Late yesterday he shows up at my shop & says, still on, I pull codes, 12x3 & then it starts to throw a new #, he starts to say, see no codes... duh. code 33! (imho it was prob. doing that the whole time?) So, run the diagnostics from the FSM, all the tests pass just fine... clear code several times over the tests & it comes back about 25 seconds after start. He has already replaced the MAF, both relays & I helped check some of the wiring... I also reset the TPS which was a little low. A few threads on here suggested checking base idle but they had to do with modified setups and/or larger TBs. He has ordered a new MAF from local parts place but I'm not sure that will stop it. I'm going to suggest he check the wiring back towards the main harness with a fine tooth comb... Anyone else have any suggestions?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Error code 33 can be caused by an open connection between the MAF and the ECM. The most common cause is a corroded contact in the connector. Contact cleaner can help here.
You might have a broken wire.
You might have a broken wire.