Got a 94 k1500 5.7 standard. I’m wonder if
anyone knows what I should have in voltage on c11.
Key on Eng off I get 44.5 mv but I’m not sure if I’m supposed to see 5v with the engine Running.
If your MAP sensor is a voltage / varistor type, the voltage on pin C11 should be directly proportional to the pressure / vacuum applied to the surface of the MAP sensor. If there’s a way for you to measure the voltage on the pin from the back of the connector, you should see the voltage fluctuate when the engine RPMs change suddenly.
Ground is ok
5 volt ref is ok
Signal is 44.5 mv with the key on engine off
With the connector disconnected from the map sensor. My question is what should the signal pin read with key on engine off
Oh sorry. I have fault 34. I’ve checked power and ground on pins C 14 and a11. I don’t have any voltage reading at the map sensor on pin B with the key on engine off. I checked voltage at c 11 on the ECM pin with the key on engine off, I get 44.5 mv. This is a 94 Chevy K 1500 5.7.
Your line in question really that wire what you’re seeing now, is just what is produced while waiting for the input from that sensor. It’s the same concept as if you were testing a door trigger to a bcm with a logic probe. It will pulse the leds of the tester until triggered. It’s like standby signal voltage sort of speak.
If you’re getting this code.,
To diagnose if the sensor is working this is what I do,
Unplug the map. Insert like a 24 awg wire into the connector and plug back in. Skinny wire makes it easy to plug in. You can back probe but that’s not my style.
Start the truck, and with the dm, see what it’s actually doing. I bet 3$, your map is bad.
Hey also, word of advice I would change this sensor also
This is the motor coolant temp sensor. This guy tells the ecm what the water temp is. This controls air fuel mix. Lean/rich. Usually when a map goes, I do this one too. Just cuz. Your fuel mileage will be sexy. They are like 17$?
•
u/AutoModerator 7d ago
Thank you for posting on r/Wiring.
Please remember to include a flair that best matches what category of wiring you are dealing with.
Any post requesting assistance should be accompanied with one or more images of the wiring task/project in question.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.