code 34- Map sensor voltage low
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Teching In
Joined: Apr 2006
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code 34- Map sensor voltage low the service engine light ceme up today, then went away then came back. i know what the map sensor is but what would cause the voltage to be too low. i just fixed one hting then this pops up 
. it seems if i am cruising at low rpm's in a higher gear at like 50 mph, it decellerates alot faster than usual?
. it seems if i am cruising at low rpm's in a higher gear at like 50 mph, it decellerates alot faster than usual? 
I just had this, it basically means either the map sensor is bad or there is a problem with the wiring either to the map sensor. the map sensor is pretty important because it controls several key parameters regarding timing and other things, so if the computer can't read it that can affect driveability somewhat.
what you have to do is check the voltage between the black and grey wires on the connector with the key on (engine off), it should be 5v. if it's not then there is a problem in the wiring of those, if it is then check the voltage of the green wire while the engine is on and the connector is attached to the sensor, if it's very low (less than 0.5v) then the sensor or connector is bad. If it's good (more than 1v) than there is a problem in the wiring somewhere with that wire to the pcm.
also sometimes it's just the connector that is bad.
what you have to do is check the voltage between the black and grey wires on the connector with the key on (engine off), it should be 5v. if it's not then there is a problem in the wiring of those, if it is then check the voltage of the green wire while the engine is on and the connector is attached to the sensor, if it's very low (less than 0.5v) then the sensor or connector is bad. If it's good (more than 1v) than there is a problem in the wiring somewhere with that wire to the pcm.
also sometimes it's just the connector that is bad.
Thread Starter
Teching In
Joined: Apr 2006
Posts: 33
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alright well i checked the wires and voltage. they are fine, then i injected the sensor with gasoline and cleaned it. after drying i put it back on the light came on again, then went off shortly and stayed off for about 3 days. drove perfect. now it is back on so i am just goign to buy a new sensor. question is: how much does one cost. for some reason it takes 2 years to search on my computer and murrays is closed right now.
Teching In
Joined: Jul 2021
Posts: 13
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From: Melbourne, Australia
I just had this, it basically means either the map sensor is bad or there is a problem with the wiring either to the map sensor. the map sensor is pretty important because it controls several key parameters regarding timing and other things, so if the computer can't read it that can affect driveability somewhat.
what you have to do is check the voltage between the black and grey wires on the connector with the key on (engine off), it should be 5v. if it's not then there is a problem in the wiring of those, if it is then check the voltage of the green wire while the engine is on and the connector is attached to the sensor, if it's very low (less than 0.5v) then the sensor or connector is bad. If it's good (more than 1v) than there is a problem in the wiring somewhere with that wire to the pcm.
also sometimes it's just the connector that is bad.
what you have to do is check the voltage between the black and grey wires on the connector with the key on (engine off), it should be 5v. if it's not then there is a problem in the wiring of those, if it is then check the voltage of the green wire while the engine is on and the connector is attached to the sensor, if it's very low (less than 0.5v) then the sensor or connector is bad. If it's good (more than 1v) than there is a problem in the wiring somewhere with that wire to the pcm.
also sometimes it's just the connector that is bad.
