CEL (check engine light) not working- Can't pull codes!
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Freshman User
Joined: Mar 2015
Posts: 46
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From: Clemson, SC
CEL (check engine light) not working- Can't pull codes!
I'm trying to pull codes on my 1990 F150 XLT Lariat 5.0 AOD trans. I went to do the KOEO test, and my check engine light wouldn't come on. It doesn't flash on when the truck cranks either. I just swapped out the illumination lights in my gauges, so I know the bulb is good because I tested it. It wasn't working before the swap either, i just never paid much attention to it, but I don't think it has anything to do with the LED swap. I visually inspected the printed board on the instrument panel when I had it out, and I couldn't see any damage. All the warning lights are still incandescent bulbs, and the rest of them work fine. I also checked both the instrument illumination fuses (#4 & #10) and they are fine.
Any ideas on what might be keeping the CEL from cutting on?
I know I can check the codes with an analog voltmeter, but I don't have one and would rather not purchase one. And nobody local has a STAR tester, except for maybe going to the dealer and paying for the service, in which case i'd rather just buy the voltmeter and do it myself.
Thanks for the help!
Any ideas on what might be keeping the CEL from cutting on?
I know I can check the codes with an analog voltmeter, but I don't have one and would rather not purchase one. And nobody local has a STAR tester, except for maybe going to the dealer and paying for the service, in which case i'd rather just buy the voltmeter and do it myself.
Thanks for the help!
Postmaster
Joined: Nov 2011
Posts: 3,533
Likes: 17
From: SW Florida
Okay well since you don't want to buy an analog meter just hook up a incandescent bulb instead. All you're doing is looking for pulse train.
Or just buy this:
To find your problem with the engine light you'll need to check continuity. I like to start where the problem is (bulb socket) and work my way back towards the source. So start by verifying no power at bulb socket, then next I'd check the connectors at the back of the cluster, then next I'd need a schematic to find out if there's any connectors between there and the PCM, and trace all the way back.
Or just buy this:
To find your problem with the engine light you'll need to check continuity. I like to start where the problem is (bulb socket) and work my way back towards the source. So start by verifying no power at bulb socket, then next I'd check the connectors at the back of the cluster, then next I'd need a schematic to find out if there's any connectors between there and the PCM, and trace all the way back.
Thread Starter
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Freshman User
Joined: Mar 2015
Posts: 46
Likes: 2
From: Clemson, SC
Okay well since you don't want to buy an analog meter just hook up a incandescent bulb instead. All you're doing is looking for pulse train.
Or just buy this:
Amazon.com: INNOVA 3145 Ford Digital Code Reader: Automotive
To find your problem with the engine light you'll need to check continuity. I like to start where the problem is (bulb socket) and work my way back towards the source. So start by verifying no power at bulb socket, then next I'd check the connectors at the back of the cluster, then next I'd need a schematic to find out if there's any connectors between there and the PCM, and trace all the way back.
Or just buy this:
Amazon.com: INNOVA 3145 Ford Digital Code Reader: Automotive
To find your problem with the engine light you'll need to check continuity. I like to start where the problem is (bulb socket) and work my way back towards the source. So start by verifying no power at bulb socket, then next I'd check the connectors at the back of the cluster, then next I'd need a schematic to find out if there's any connectors between there and the PCM, and trace all the way back.
Thread Starter
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Freshman User
Joined: Mar 2015
Posts: 46
Likes: 2
From: Clemson, SC
So weird thing, I hooked the bulb up and did both tests. As I'm about to cut the engine, I look down and the CEL is on. Cut off and hit the key again, and it cuts on then off when it cranks like its supposed to. Don't know what fixed it but it's good now
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