Pulling my hair out (what's left of it) over SES Code 26

Bob · 09-18-2003, 04:09 PM

Longtime reader - First time poster......

Bought a used '93 SL1 (125K miles, auto, a/c) for my oldest to use for college transpo. Initially it had about between 9 and a zillion SES codes but by searching this board and accessing the Alldata TSB and diagrams, I was able to repair the following:

Reverse slam (broken valve body line control pressure spring)
Overheating (Temp sensor)
Wasted brakes (leaking wheel cylinders)
High idle and EGR fault (leaking EGR diaghram)
Bizarre upshifting (faulty Turbine speed sensor connector)
Sparkplugs that must have original (they had a gap of .120)

All this, in addition to a complete tune-up and fluid flush, has it riding and purring like a kitten except.......the infamous SES code 26.

I get a code 26 when the engine warmed-up as soon as the speedo hits approximately 60 mph (I can drive 50-55mph all day with no light). Once I go over 60, it stays on until I slow back down in the 50 range (it'll extinguish while on the off-ramp for example).

All other indicators are normal. It runs great, idles smooth and low (around 650 rpm), shifts fine, a/c works, cooling fan works, the EGR and Cannister solenoids ohm out at 50 and 52.

Can someone tell me what is energizered under those conditions (and only those conditions) that would cause the light?

Thanks - Bob

RiceRocket · 09-18-2003, 05:17 PM

A problem with OD maybe?

Bob · 09-18-2003, 06:24 PM

I thought about that earlier but, the indication is not affected by OD. If I drive flat and level at 55 mph in OD = no light; a few seconds after easing up past 60 = light. go figure......

3dinmind · 09-19-2003, 07:14 PM

Bad speed sensor on the front axle? Probably doesn't have ABS, right?

RiceRocket · 09-19-2003, 07:29 PM

Doesn't the reader give a discription for that code? That would be really helpful or maybe it doesn't cuz the car is too old.....and maybe I don't know what I'm talking about...

Ok seriously though, if you get the Haynes (sp?) manual it should tell you what that code means and it should be pretty easy to go from there.

btw, I like your sig bob.

If it was the speed sensor wouldn't the light stay on as long as the car was moving, if not all the time?

You replaced the entire EGR right?

I really don't know, that is just weird as all hell.

You could do like I'm doing to fix my hesitation problem.....go through and replace every sensor 1 by 1..... maybe its a tranny problem?

Ah! Maybe its an oil/coolant circulation problem? Is it possible that at a high speed the oil pump starts to suck and die?

wolfman · 09-20-2003, 03:17 AM

It actually sounds like the CCPS or EGR solenoids to me despite your test results. A quick way to check...unplug the electrical connection for the CCPS and reset the PCM codes then drive the car. If the SES light stays off then, the CCPS is the culprit. If it does not, repeat the test this time unplugging the EGR solenoid electrical. If it still comes on, other things to check...

HOT light bulb burned out
OIL light burned out
LOW coolant light bulb burned out
Loose connection at PCM main harness connection
Loose connection at PCM connector at top of autotransaxle pan
LAP BELT light burned out and/or bad PREST module

monkeyracing · 09-20-2003, 04:47 AM

Yup, i got code 26 when I had a burned out bulb in my dash. That sucked.

Jim

Bob · 09-20-2003, 12:26 PM

Thanks to all who have posted so far -
I've cleaned and reseated numerous connections (including the speed sensor) - btw..no ABS on this car, we got the boy a basic vehicle so dad doesn't have to mess around with fixing power windows and stuff this winter when it's minus 4).

Anyway, this weekend I'll be pulling both solenoids out and hook them up to my ohm meter and put a heatgun on them (a lot better alternative then crawling under a hot car. I'm leaning more and more towards the CCPS since it runs great, shifts smooth and gets great mileage; a fact I confirmed when I drove 30 miles to work the other morning on 'E' because the boy didn't gas it and the local stations weren't open yet (considered dumping the gas from my chainsaws in there.....just kidding)

Wolfman - I like the idea of pulling the CCPS. Two questions:

Do I pull it with the car running (does the PCM do a start-up query of connections) or just pull it, reset and go?

Do you know under what conditions the PCM sends a command to the CCPS solenoid? (i.e. TPS above X%, vehicle speed above X mph, trunklight on, radio on AM, etc....)

Once I get this squared away, the only thing work is the driver's side auto seatbeat (zips back and forth about half-way on the track.....got it locked in the pillar position with the motor disconnected)

Thanks again......Bob

**Ssicarman** · 09-20-2003, 08:37 PM

I'm going with Wolfman on this. The EGr solenoid or the cannister purge solenoid would be the prime suspects. These two solenoids usually fail under higher heat situations and would not normally set a code until the car is driven for a longer/higher speed distance. If you checked the solanoids when they were relatively cool then they would check as good, the range that you got is normal. Check them when they are so hot that you can't really hold them. If you have then off of the car a nice way of heating them is to lay then on the hot exhaust manifold after the engine is off. This should get them hot enough to give the high resistances that would cause a code to be set. Just make sure that you don't melt them down on the manifold.

wolfman · 09-21-2003, 03:35 AM

Quote:

Originally Posted by Bob

Wolfman - I like the idea of pulling the CCPS. Two questions:

Do I pull it with the car running (does the PCM do a start-up query of connections) or just pull it, reset and go?

Do you know under what conditions the PCM sends a command to the CCPS solenoid? (i.e. TPS above X%, vehicle speed above X mph, trunklight on, radio on AM, etc....)

Thanks again......Bob

Pull the electrical connector BEFORE you start the car. The PCM (OBD1 on a 95 and earlier) only looks for a faulty voltage reading from these two solenoids NOT a complete lack of voltage, so if you pull the connector off a bad solenoid, reset the PCM and then drive the car with the faulty solenoid disconnected, the PCM will not "see" the faulty voltage and not set an SES light. Its a simple and "free" way to test either/both of the solenoids. Another method is to install a resistor inbetween the connector pins of the appropriate test resistance ratings with it disconnected from the solenoid and see if the light also stays out, but this is really more trouble/work than is necessary. If memory serves, EGR solenoid is energized when the PCM detects normal operating temp has be reached, thottle position above idle but not at wide open throttle, rpm at 2500 or better, vehicle in motion as detected by the VSS (vehicle speed sensor) input. CCPS "on" threashold is very similiar.