ECM Bad? CTS Woes. Help!!
Thread Starter
Tech Contributor
Joined: Oct 2008
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From: Custer, WI
ECM Bad? CTS Woes. Help!!
I just finished installing the SuperRam for the second time and started the car up. Ran a bit rough but better than before. Before I started moving it, i plugged the laptop into it.
The coolant temperature sensor reads -38.7 and didn't move the entire time I was driving the car. The car runs pretty rough so I only took it around the block.
The car is also giving codes 33, 44, and 45. Could this be a bad ECM?
Its an '870 ECM and I used WinALDL to log.
The coolant temperature sensor reads -38.7 and didn't move the entire time I was driving the car. The car runs pretty rough so I only took it around the block.
The car is also giving codes 33, 44, and 45. Could this be a bad ECM?
Its an '870 ECM and I used WinALDL to log.
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Joined: Jun 1999
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From: Merritt Ils Fl
With out going into detail 33 is a MAF fault (signal voltage high), 44 is a O2 sensor fault( lean exhaust), 45 is also an O2 fault( rich exhaust). All three can lead to a faulty ECM. My suggestion is to lay hands on an 85 FSM and do the diagnostics. That is the best way. If you can find a known good ECM do the swap and see if the faults are still present.
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Doesnt a bad ecm throw throw a code on its own. Like a 15 or something?
Race Director
Joined: Jun 2004
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From: WI
Check the grounds for those sensors, and check continuity on their circuits. Test the CTS, IIRC xxxx volts equal xx° temp, then warm it up or place it in cold water. Check for different volts. Could be a bad ECM yes, they don't always give the bad ECM code. Follow the FSM chart for that.
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
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From: Custer, WI
I just went out to test the CTS. It said clear codes, so I disconnected the battery. Started the car, no codes except for code 24 which is vehicle speed sensor. Should I follow testing for that as well? Or just do 15 33 44 45?
This is going to be pure excitement.
Where are the grounds for the sensors? don't they ground to the ECM?
This is going to be pure excitement.
Where are the grounds for the sensors? don't they ground to the ECM?
Thread Starter
Tech Contributor
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
Just cleared codes again, and started it. Got codes 42, 43 and 24.
Edit: Update: Now when I drive it, I am not getting an instant or avg mileage reading on the digidash. I am almost certain its the ECM.
Edit: Update: Now when I drive it, I am not getting an instant or avg mileage reading on the digidash. I am almost certain its the ECM.
Last edited by Pwnage1337; Jul 11, 2010 at 11:43 PM.
Race Director
Joined: Jun 2004
Posts: 13,961
Likes: 707
From: WI
You haven't done enough testing yet to be certain it's the ECM. There are many grounds, and they cannot ground to the ECM. Check your FSM for the ground charts. Each circuit diagram will also show it's ground.
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