TR sensor voltage too high
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TR sensor voltage too high
My truck (1995 F-150 4x4 with 5.0 and 4r70w) has been idling really rough and stalling, especially in reverse when hot. I was getting code 668: Transmission range sensor circuit above maximum voltage.
I just got me the factory service manuals, and checked the resistance across the TR sensor and everything is within range. Sensor input voltage to the TR sensor is supposed to be 5 volts, is around 8 volts. Does this mean the PCM voltage regulator is bad and the whole PCM needs to be replaced? I still need to get ahold of the Powertrain Control/Emissions Diagnostics Manual which probably has this stuff in it.
I'm also wondering if I damaged the transmission driving it like this. I guess if the PCM is getting the wrong signal from the TR sensor it could tell the EPC solenoid the wrong thing and pressure getting too high. The overdrive off light started flashing a week ago and I parked the truck. How do I tell why the light is flashing? I moved it from one spot on the driveway to another today and it made a loud clunk when going from reverse to drive, didn't do that before.
I just got me the factory service manuals, and checked the resistance across the TR sensor and everything is within range. Sensor input voltage to the TR sensor is supposed to be 5 volts, is around 8 volts. Does this mean the PCM voltage regulator is bad and the whole PCM needs to be replaced? I still need to get ahold of the Powertrain Control/Emissions Diagnostics Manual which probably has this stuff in it.
I'm also wondering if I damaged the transmission driving it like this. I guess if the PCM is getting the wrong signal from the TR sensor it could tell the EPC solenoid the wrong thing and pressure getting too high. The overdrive off light started flashing a week ago and I parked the truck. How do I tell why the light is flashing? I moved it from one spot on the driveway to another today and it made a loud clunk when going from reverse to drive, didn't do that before.
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From: Easton,Ks
The KOEO and continuous memory code are not the same read out.
The continuous memory code wants for you to run the drive cycle test and then check for codes.
But I will post for KOEO below.
KEY ON ENGINE OFF (KOEO) DIAGNOSTIC TROUBLE CODES (DTCS) 668.
DTC 668 indicates an open in the TR circuit.
Possible causes:
-- Transmission Range not in Park during Self-Test.
-- Misadjusted linkage.
-- Open or short in harness circuits.
-- Damaged TR sensor.
-- Damaged PCM.
The continuous memory code wants for you to run the drive cycle test and then check for codes.
But I will post for KOEO below.
KEY ON ENGINE OFF (KOEO) DIAGNOSTIC TROUBLE CODES (DTCS) 668.
DTC 668 indicates an open in the TR circuit.
Possible causes:
-- Transmission Range not in Park during Self-Test.
-- Misadjusted linkage.
-- Open or short in harness circuits.
-- Damaged TR sensor.
-- Damaged PCM.
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Yeah that was a cm code. I did the test again and got KOEO code of 654, transmission selector now in park as well as several other cm codes. I found the open circuit at the TR sensor connector. Going to replace the connector since it's pretty cracked and brittle and won't sit on there right.
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danjohnson67
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Apr 29, 2009 09:12 AM
