1993 Code 26 - Quad Driver Module #1 Circuit
Thread Starter
Instructor
Joined: Oct 2012
Posts: 104
Likes: 6
From: Long Beach MS
1993 Code 26 - Quad Driver Module #1 Circuit
I recently installed a 700R4 Level 4 Transmission in my 93, along with a Remote Transmission Cooler. Previously, I didn't have a Transmission Cooler. My installer got the 12 volt key on power from the very front left of the car, which I believe is the Evaporator Canister. I see where this is part of the Quad Driver, along with the EGR Solenoid, Air Solenoid Relay and Air Bypass Solenoid Valve. After the installation, the SES Light came on. Would getting the power for my Cooler Fan from the Evaporator Canister Purge Solenoid cause the SES Light to come on? If so, where would be the best place to get 12 volt key on power? If not, short of following the FSM Troubleshooting Procedure, would you have any recommendations on what might be causing the Code 26? I've got Long Tube Headers, and the EGR is deleted, with exception to the EGR Solenoid. I was told that removing the EGR Solenoid would cause the SES Light to come on. Since the header install and EGR delete, I haven't had any problems for 2-3 years with any DIC Codes or SES Light. Thanks.
Instructor
Joined: Apr 2018
Posts: 125
Likes: 20
In general, it's a bad idea to take electric power for a fairly heavy inductive load like a cooling fan motor form a circuit intended to power much smaller loads like solenoid valves. You could try using a relay wired to your key-on source and battery power, that might reduce the load enough not to eliminate the code. Sorry, I'm not that familiar with the circuitry of a '93.......
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Quad driver is like a circuit breaker. Excessive current draw ( shorted circuit) causes the quad driver fault. You could disconnect each solenoid one at a time to isolate circuit, see with one stops 26 from resetting. Then evaluate that circuit.
