LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

code 26 & 28 HELP PLEASE

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Old Nov 5, 2007 | 08:31 AM
  #1  
redington's Avatar
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code 26 & 28 HELP PLEASE

Code 26- EVAP purge control solenoid circuit. EVAP solenoid circuit indicated as faulty. Check wiring and connections.


Code 28- Transmission Range (1994-95). Check the transmission control range circuit for any opens or shorts. Verify transmission range pressure switch is working. Range "A" is on ecm pin "C28" to terminal "N" on transmission plug in, Range "B" is on ecm pin "C29" to terminal "R", Range "C" is on ecm pin "C30" to terminal "P".

Thats what i found on the net. I have a 93 so i dont know about code 28 i posted. Does anyone know 28? What do they mean? After i got the codes checked the car ran at 500 rpm on idle. Any help would be awsome. Mods are in sig

Thanks
_ mike
Old Nov 5, 2007 | 09:48 AM
  #2  
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From: Hell was full so they sent me to NJ
Go to Shoebox's LT1 code list, and look at the far right-hand column for the 93 codes.

http://shbox.com/1/Dtcs.htm

DTC 26:
Quad-Driver Module (QDM) #1 circuit
applies to:
- AIR pump relay circuit
- EGR solenoid
- EVAP solenoid

DTC 28:
Quad-Driver Module (QDM) #3 circuit
applies to:
- fan control relays
- a/c relay

Why did you have to "get the codes checked"? You can flash them on the SES light using a paper clip on the ALDL connector..... see instructions on Shoebox's website:

http://shbox.com/1/dlc2.jpg
Old Nov 6, 2007 | 02:14 PM
  #3  
redington's Avatar
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it was free and easy to stop by a shop and have it done. I dont have AIR or EGR so how would i trouble shoot these codes?
Old Nov 6, 2007 | 05:29 PM
  #4  
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From: Hell was full so they sent me to NJ
If you have deleted the EGR solenoid and/or removed the AIR pump without having a good fuse in the circuit, it will cause DTC 26.

Are your fans working correctly, or do you have an add-on fan switch? That could cause DTC 28. Also could be a problem with the A/C relay.
Old Nov 11, 2007 | 11:18 PM
  #5  
redington's Avatar
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how would i test the ac realy? Would this cause the lights to flicker if it was the relay?
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