Coolant temp sensor

[Jack Schneider]

Hey guys! I’ve been wanting to replace my coolant temp sensor because it’s cheap and easy and throwing new parts in a 26 year old truck can’t hurt. BUT apparently there’s 2 of them? One for the PCM and another for the gauge? The gauge works so that one is good, but is there a difference between the two? I believe the gauge one is in the side of the head and the PCM one is near the thermostat. Just wondering if there’s a difference between part numbers

 

[Joe Dirte]

I think the one on the head has a long pigtail so it would be to different parts.

 

[Jack Schneider]

I just realized the main one has two wires and the gauge sensor has one wire. So I ordered this and hopefully it’ll work!
https://www.amazon.com/gp/aw/d/B000C9I038/ref=ya_aw_od_pi?ie=UTF8&psc=1

 

[RichLo]

There is a difference between them. The PCM one is the normal one that you ordered. The gauge one is rather difficult to find and parts stores look at you dumb when they bring out the 2-wire one and you say its the wrong one. I have a thread from a couple years ago somewhere in here that somebody replied to with the correct part number for that one. Just search my name and coolant temp sensor or something to find it.

 

[Jack Schneider]

There is a difference between them. The PCM one is the normal one that you ordered. The gauge one is rather difficult to find and parts stores look at you dumb when they bring out the 2-wire one and you say its the wrong one. I have a thread from a couple years ago somewhere in here that somebody replied to with the correct part number for that one. Just search my name and coolant temp sensor or something to find it.

I actually found that one first!
https://www.amazon.com/ACDelco-213-..._rd_t=40701&psc=1&refRID=ZFTAA7WMK8VQQK8WPJZ1

 

[Jack Schneider]

Almost ordered it but luckily I did more research

 

[Mike Napolitano]

Hey guys! I’ve been wanting to replace my coolant temp sensor because it’s cheap and easy and throwing new parts in a 26 year old truck can’t hurt. BUT apparently there’s 2 of them? One for the PCM and another for the gauge? The gauge works so that one is good, but is there a difference between the two? I believe the gauge one is in the side of the head and the PCM one is near the thermostat. Just wondering if there’s a difference between part numbers

Yes there is, the the one near the thermostat is for the pc and is a two wire sensor, the one on the driverside head is a single wire sensor

 

[Ken K]

The ACDelco 213-928 is definitely the temp sensor input for the ECM/PCM for changing idle speed, fuel mixture and timing. A dash equipped with a gauge is a single wire canister type with one wire. Both change resistance with coolant temperature, but the ECM/PCM one use two wires to provide direct dedicated ground reference or 5 volts in, then monitors voltage back. The dash gauge is simpler and requires only one wire. So two sensor, each have their own task. The ACD 213-928 is used on all GM's (different models) from 1985 - 2011 / some to 2014.
This is paper service manual territory which I don't have, but sensors the ECM/PCM need inputs from, use a dedicated ground to keep voltages (Even Ground) on the same level which results in more accurate inputs.

In dealerships, for quick diagnostics, we would go to the MAP, MAF, TPS to measure ground to battery. Why? This circuit is dedicated to the control module, goes into the computer, thru the section that "Is" inputs, out of ECM/PCM thru one of 4 or 5 grounds, Via harness, usually to G100 or G102, thru block, thru cable, to battery. Standard measurement is 0.400 volts using a the voltage drop test with engine running. This is a quick test, and verifies one more thing is ok, like ECM/PCM ground...Without removing it.

Sorry, the teacher in me is coming out. Why are you replacing it? Check it with a scan-tool and infrared thermometer and compare. Same with gauge.

 

[Kevmore007]

The ACDelco 213-928 is definitely the temp sensor input for the ECM/PCM for changing idle speed, fuel mixture and timing. A dash equipped with a gauge is a single wire canister type with one wire. Both change resistance with coolant temperature, but the ECM/PCM one use two wires to provide direct dedicated ground reference or 5 volts in, then monitors voltage back. The dash gauge is simpler and requires only one wire. So two sensor, each have their own task. The ACD 213-928 is used on all GM's (different models) from 1985 - 2011 / some to 2014.
This is paper service manual territory which I don't have, but sensors the ECM/PCM need inputs from, use a dedicated ground to keep voltages (Even Ground) on the same level which results in more accurate inputs.

In dealerships, for quick diagnostics, we would go to the MAP, MAF, TPS to measure ground to battery. Why? This circuit is dedicated to the control module, goes into the computer, thru the section that "Is" inputs, out of ECM/PCM thru one of 4 or 5 grounds, Via harness, usually to G100 or G102, thru block, thru cable, to battery. Standard measurement is 0.400 volts using a the voltage drop test with engine running. This is a quick test, and verifies one more thing is ok, like ECM/PCM ground...Without removing it.

Sorry, the teacher in me is coming out. Why are you replacing it? Check it with a scan-tool and infrared thermometer and compare. Same with gauge.

Hey, just wondering if you still monitor this thread. You sound like you know exactly how this system works. Thanks for the info, and hope you are still on here helping people.

 

[AuroraGirl]

The ACDelco 213-928 is definitely the temp sensor input for the ECM/PCM for changing idle speed, fuel mixture and timing. A dash equipped with a gauge is a single wire canister type with one wire. Both change resistance with coolant temperature, but the ECM/PCM one use two wires to provide direct dedicated ground reference or 5 volts in, then monitors voltage back. The dash gauge is simpler and requires only one wire. So two sensor, each have their own task. The ACD 213-928 is used on all GM's (different models) from 1985 - 2011 / some to 2014.
This is paper service manual territory which I don't have, but sensors the ECM/PCM need inputs from, use a dedicated ground to keep voltages (Even Ground) on the same level which results in more accurate inputs.

In dealerships, for quick diagnostics, we would go to the MAP, MAF, TPS to measure ground to battery. Why? This circuit is dedicated to the control module, goes into the computer, thru the section that "Is" inputs, out of ECM/PCM thru one of 4 or 5 grounds, Via harness, usually to G100 or G102, thru block, thru cable, to battery. Standard measurement is 0.400 volts using a the voltage drop test with engine running. This is a quick test, and verifies one more thing is ok, like ECM/PCM ground...Without removing it.

Sorry, the teacher in me is coming out. Why are you replacing it? Check it with a scan-tool and infrared thermometer and compare. Same with gauge.

Hey, just wondering if you still monitor this thread. You sound like you know exactly how this system works. Thanks for the info, and hope you are still on here helping people.

The procedure kev discussed in this post you ask about is called a ground credibility test and is done best by probing as mentioned yes but a PCM output should be enabled/cycled this could be an electric cooling fan or something else , in an old enough truck putting it in Field Service Mode would do this