1986 mustang has three DTC's need help

65coupe88hatch · 10-10-2009, 07:42 PM

ran my 86 gt 5.0 5spd on the new scanner i got and recieved three codes,

DTC54 intake air charge temp sensor circuit open; vane air flow sensor out of range

DTC67 1.neutral pressure switch NPS circuit failure, circuit open (3.0 map, 3.0 maf sfi 3.8sfi)
2. cars only, neutral drive swtich nds circuit failure circuit open; or ac input high
3. cars only, manual lever position mlp sensor out of range; or ac input high (4.9 map, 5.8 map)

if someone could help me understand these i would greatly appreciate it, i got the dtc54 twice and the dtc67 once, using the snap on ya3120 Can obd 1 and obd2 scanner. and it was the koeo test.

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lxman1 · 10-11-2009, 01:57 AM

#1 indicates that it is not seeing the AIT sensor. It is either unplugged or possibly bad. It is the sensor on the driver side of the intake in the #5 runner.

#2 Shows that the neutral switch on your T-5 transmission is not closing when in neutral.

65coupe88hatch · 10-11-2009, 10:03 AM

what does the intake sensor do? and what could be some of the drivibility issues if it isnt plugged in or doesnt work any longer?

as for the neutral switch what does that mean? do i need to replace it? and again what kind of problem can i see from it being bad?

mjr46 · 10-11-2009, 11:20 AM

run the koeo/koer test with the trans in nuetral, not in gear

lxman1 · 10-11-2009, 11:56 AM

This is true, may be fine if you didn't test it in neutral.
The IAT senses the intake air temp and uses this info to help determine the correct air/fuel mixture and timing. It needs to work for the ECM to give you the best performance/drivability.

65coupe88hatch · 10-11-2009, 05:17 PM

i cant remember if i did the test with the trans in neutral or not... hm ill do it again and check it with the trans in neutral. as for the intake sensor where exactly is it located on the engine and what does it look like?

86 5.0L · 10-11-2009, 05:34 PM

on the lower, near the number 6 runner if I recall correctly

lxman1 · 10-11-2009, 09:28 PM

Driver side in between the front and second fuel injector.
It is just hidden behind the vacuum line laying on top of the distributor. It is at about a 45 degree angle with green and black wires.

65coupe88hatch · 10-11-2009, 09:31 PM

does the plenum need to be removed to change it?