code 26 error

[drhhsmith]

hi having issues with a code 26 error. now i dont believe that there ever was a resistor relay in the red terminal block for the secondary injectors in the first place but car ran trouble free for a long time . I ran the car hard one night had check engine light come on . noticed a broken vacum line near the check valve near the back of the engine bay as well as fuel tank to canister had rotted away fix all of these and cannot find issue any suggestions please would be appreciated

[Bibs]

Hi and welcome Dave. Have you tried running Espritmon, it can help diagnose Code 26 errors.

 

[Qavion]

Unfortunately, Code 26 covers a lot of things:

26A:

Radiator Fan Relay

Wastegate solenoid

Canister Purge Solenoid

Check Engine Lights

26B:

ROM relay (?)

A/C Control Relay

Engine Overheat Relay

Throttle Jack Solenoid Relay

Secondary Injectors

I think Espritmon narrows the choice down to A or B, but I can't remember if it goes further than that.

I think I've cleared a Code 26 before by resetting the plugs on the secondary injectors. Have you done a resistance check on the injectors?

Cheers

Ian.

[drhhsmith]

 i have an ob1 2 tech reader and the freescan prgram but i cant get any adaptors to fit so i can read the codes at the abck of the engine bay is  a ten pin connector that nothing fits . is this the only read out location on the 1991?. i have tried to reset plugs on secondaries and searched for any other issues i can find on the vehicle . point of note before this code 24 happened the throttle jack for warm up would work about half the time here and there not constant on warm up as well

 

thanks a lot guys for the responses

[Vulcan Grey]

the Lotus uses the Opel style ALDL connector

 

[Qavion]

Quote

point of note before this code 24 happened the throttle jack for warm up would work about half the time here and there not constant on warm up as well

It could be a clue. If there is nothing physically wrong with the throttle jacking mechanism and the hose to the throttle jack isn't collapsing when vacuum is applied and subjected to engine heat, the solenoid could be faulty and generating a code. The engine ECU may not know what is happening with the mechanism and hoses, but it does check the solenoid electrical circuit.

 

There used to be ALDL plug to serial plug adaptors for old laptops, but now you can buy ALDL to USB.

[tmusc]

This is a older gm OBD1 system. if you do a quick search you can find out which pins to short out. there is no 26a or 26 code. its all 26. as far as i remember if the secondary injectors short out you will get a code 26. Unfortunately on my car the only way to fix it was replace the secondary injectors and the ecm. ecm is easily available. the cal pak is not. DO NOT give up your ECM you need the cal pak in it to put into the new ECM. The ECM part number from GM is 

1228708

https://www.amazon.com/ACDelco-1228708-Engine-Control-Module/dp/B000C9D2T0/ref=sr_1_1?ie=UTF8&qid=1489023447&sr=8-1&keywords=1228708

 

Edited March 9, 2017 by tmusc

[fjmuurling]

I think there is a litle bit confusion about code 26 A and B.

 

The CEL light in the car can only show if there is a Code 26 present, not if it is A or B.

 

The EMH manual describes the different Codes 26 A and B.

In the ECU there are 3 QDM drivers which each have their own Fault Output. The Software in the ECU checks if these 3 Fault signals are present and if there is a QDM fault it will set a bit. However only two bits are used for 3 possible QDM Faults. One bit is used for the Fault of one QDM, when one of the other two (or both) is (are) Faulty then the other bit is set.

 

The Tech1, Freescan and Espritmon can read the above bits and therefore display a Code 26A or 26B Fault.

There is one small error in Freescan it will display the right Code (A or B) but the descriptions are wrong. The description at 26A is the one for 26B and the other way around.

 

Hope this clears some things up.     

 

[sanj]

A missing resistor module in the red socket will most assuredly cause a code 26, so you might as well start there.