Guys
My BNL has a stock 84 Z28 auto,carb. SES light is coming on with code 15, 23 and 44
im not sure what causes low temp on CTS, but if i replace sensor, code 15 should go away?
code 23, Low temperature at manifold air temperature sensor not exactly sure what to check here.
code 44, O2 sensor lean. if i replace O2 would that take care of that code?
If anyone can give any suggestions on how to trouble shoot, i would appreicate it. thanks

 

I didn't think carb cars had o2 sensors or manifold air temp sensors. There may be a different list of codes for a carbed car or you have the wrong ecm. I really dont know what to tell you, more or less Im typing this to purely suscribe to this thread.

 

i got the codes off this site. i guess those codes are for efi motors.

 

anyone have codes for carb cars? 15, 23,44, anyone?

 

edit: five7 coms through .

 

Computer controlled carbs use an O2 sensor.

Code 15, Low temperature indicated at engine coolant temp sensor, aka "CTS voltage high". Usually a short from the 5v signal to return line. Could be the CTS itself, but could be a short in the wiring somewhere.

Code 23: Note it says, "Low temperature at manifold air temperature sensor OR Throttle position sensor error". The first is the EFI code, the 2nd is the CC carb code. You've got a TPS problem.

Code 44, O2 sensor lean. This almost always means the O2 sensor is weak and needs to be replaced. Can be a poor connection, though.

 

You can check the CTS by shorting the wires at the pigtail after clearing your codes. This will 'confuse' the ECM into thinking the CTS is at max temp if the wiring is good.

The TPS has probably truly failed and will likely need to be replaced. To check: connect a DVM (or common volt meter) to the middle and bottom leads (B&C, right?), WITH the TPS still plugged in, it should read near 0.40 volt at idle position and near 4.0 volt at WOT. It should vary linearly between the two positions. Key in 'run' engine does not need to be running.

O2 is almost a regularly replaced tune up item.

 

Since it's already reading high voltage, you might want to just disconnect it and clear the codes. If it then throws a Code 14, that's a good indication that the CTS is bad.

(Unless I've got the CTS operation backward in my head.)

 

I've also been around enough to know that no matter how certain you are, there's always the chance....

You made me physically check but luckily the TA just got a new battery last night and although the new motor hasn't been fired up (tomorrow, maybe?) it was in the garage with most every thing connected. CTS open read 2 degrees/shorted 320 degrees (F). I quit doing these 'black box' checks a while back when I finally got an Autoxray scanner and I haven't looked back. It amazes my friends as well.

I was thinking one thing, writing another. Most likely cause of the 14 is a short on the pigtail of the CTS. Those pigtails stick up right at the AIR tube crossover and take a lot of abuse. Disconnect it and check for continuity between the two leads at the pigtail. Wiggle it around, see how it looks. A replacement can be picked up at AZ or one of the others.

My check will work for a 'low temp' CTS fault. It's only a thermistor receiving a 5 volt signal and returning <= 5 volts. Your check is close although it would indicate that the pigtail was bad (not the CTS). The ECM will also look at a few other things before throwing the 14. A 'time out' so to speak. So it won't throw the 14 right away.

 

Hah! There was no certainty involved at all! I was speaking purely theoretically, I've never actually played with it on the car.

So, Tom, listen to naf, not me. . .