Can a DTC of 23 throw an SES light?

[Turbo6Smackdown]

Threw the Steve Monroe throttle body on last night and could NOT get the IAC to give me anything above 00 lol. Only when I backed my idle air adjustment screw allll the way out did it start to march upwards but I can't obviously run like that so I just kept on trying. IAC reset didn't do anything either. Finally said screw it and capped off the pcv. TOTALLY different car now. WOW. I can't REMEMBER the last time EVERY value on my scanmaster was WITHIN SPEC lol. I mean IAC's perfect, cross counts perfect, 124 blm's, and the narrow & wide band O2's have never been steadier. Car idles like an 11.9-12.2 afr, doesn't falter or die or anything. This thing rocks now! lol. BUT, after the installation of the new throttle body, my IAT's freaking the hell out, running from - 30 to like 200 back and fourth lol, and now it's giving me my first ever mal code on my scanmaster that I can remember: 23. And now my SES light's on. How does this thing run better than EVER before, but the ses light's on now? Please tell me it's because of this stupid IAT sensor.

 

[TexasT]

Pretty much

http://repairpal.com/gm-obd-code-23

 

[Turbo6Smackdown]

Yea but that's obd. We're pre obd and even if we were, that's a standard chart - our cars are anything BUT. Isn't iat removed in our chips now? Would it still illuminate an ses light?

 

[69RSCLONE]

Not pre obd, it's obd1. We are pre obd2 which is the universal system that all cars 96 and new were required to have. Some back to 93 had obd2. Will still flag a code if faulty. Not sure how the chip is burned to use the signal, but obviously it still is monitored even if it doesn't effect the running.

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[Turbo6Smackdown]

OBD1 started in 1991 - we're aldl, aren't we?

 

[salvageV6]

Check the MAT sensor wiring as it seems like an intermittant connection.

One easy test would be to place a 5K ohm resistor across the two terminals and see if the light goes out.

It's a simple thermistor sensor two wire and they can break or the harness gets jacked up when moved/relocated.

The stock ECM won't ignore the problem even if the TT chip ignores the funky readings.

 

[Turbo6Smackdown]

Check the MAT sensor wiring as it seems like an intermittant connection.

One easy test would be to place a 5K ohm resistor across the two terminals and see if the light goes out.

It's a simple thermistor sensor two wire and they can break or the harness gets jacked up when moved/relocated.

The stock ECM won't ignore the problem even if the TT chip ignores the funky readings.

A 5K resistor. Sure. Lemme see if I have a spare in my pocket lol. (j/k) My sensor's about 3 months old It just sits there and does nothing. Could it be bad now? I'll check the wiring though. And the minute it gets fixed, does the SES light go out immediately?

 

[Turbo6Smackdown]

Ok I grabbed the sensor and the temperature that was steady at 73 started its wild fluctuations all over again from -25 to like 110 in really fast and random speeds much like looking at your narrow band 02 sensor, so something's wonky but here's what I don't understand, my ses is off lol. I can't make it go back on. Now I unplugged it and it went on, but when I plugged it back in it went off again. How fast does this sensor update? I NEVER knew this sensor to update soo quickly, so I don't know if this is a malfunction happening. Though even with the SES off the scanmaster still reads a dtc of 23. Do I pull the battery cable now to reset or what? Check with a new one?

 

[69RSCLONE]

ALDL stands for assembly line diagnostic link. Even new cars call the plug under the dash an ALDL

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[Turbo6Smackdown]

ALDL stands for assembly line diagnostic link. Even new cars call the plug under the dash an ALDL

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NO ONE under 40 has ever even heard of ALDL, much less that being the industry standard lol. In class (auto technology at the local college) everyone looks at me funny when I say that lol. I think it's dead, though it's what I learned on so I'll call it that till I die.

 

[Chuck Leeper]

Car idles like an 11.9-12.2 afr, doesn't falter or die or anything. This thing rocks now! lol. BUT, after the installation of the new throttle body, my IAT's freaking the hell out, running from - 30 to like 200 back and fourth lol, and now it's giving me my first ever mal code on my scanmaster that I can remember: 23.

The IAT fault going to -30 could be why the AFR is in the 11's.
As mentioned.... wiring. Addition of the t/b has no connection to the sensor. {Other than you have screwed the pooch on the wiring, or Murphy failed the new sensor.}

 

[69RSCLONE]

I'm 37 and grew up with the OBD1 systems and learned from my fathers mistakes of going overboard with the diagnosis. Skipping, bucking, dieseling, "gotta be the computer" . Wrong, still the same old cap, rotor, wires. You could remove the ecm and not notice any difference other than the light being on. But people got scared. Same thing now with younger techs. Codes are far more specific to the actual problem, give them a OBD1 diag and watch a meltdown. First the scanner has a different plug. If there is a scanner that actually has obd1 connector in the shop it's buried under 5 years of crap. And when they finally get it plugged in and get a code, it gives a 2 digit number, say 23 for instance. What now? Replace the part? Since you can't see freeze frame, and the scanner doesn't tell you what the known good specs, it's time to use your brain, something that the new generation isn't taught anymore it seems. I work with 3 younger guys 20-29 that went to college for auto and still have trouble changing oil. I have a 71 cutlass at the shop that was dropped off as I left yesterday for drivability concerns and inop fuel gauge. Customer only allows me to work on his car and even if I didn't, no one else would have a clue.

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[salvageV6]

Wiring and sensor basically set the code immediately, so if the sensor is bad, find a 4.7K resistor they're common or read the sensor itself UNPLUGGED, at 70 degree room temp. should be around 3500 ohms with an OHMmeter test.

It's probably a bad connector or wiring being intermittant to it.

Once the sensor reads below -40 degrees it lights the light, and it will go out immediately once the sensor is working properly.

According to Wikipedia we are ALDL not OBD1, unverified info. of course.

https://en.wikipedia.org/wiki/On-board_diagnostics

 

[69RSCLONE]

You learn something new every day. Never heard of ALDL protocol before. Like you said, unverified. If that's what people want to call it go for it. I'll stick to OBD1 even if not correct. Lol. Uses the same GM-1 connection from the start in early 80's to mid 90's when obd2 started.

But to the original topic, check resistance of sensor and if OK start checking for breaks in wires to sensor. Also check chip and powerlogger(if using) for good connection. Had some screwed up readings a few weeks ago for a powerlogger board that worked itself loose.

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