No AC with codes

[Angelo217]

2006 Chevy tahoe 5.3l z71 242k miles
Had intermittent AC issues for a while. Ac does not work barely at all anymore, except for occasionally in the morning cold the compressor will kick on a few times.

Replaced AC pressure sensor, replaced ac pressure switch on accumulator, replaced orifice tube, compressor is newer, accumulator is newer. Blower motor works.

Compressor relay will not get power, only when jumping the relay the compressor is functional. We cleared my codes p0651, p0452 5v reference and a Evap low voltage code. With those codes cleared and orifice replaced compressor was working ac worked fine for 15 mins. Second check engine came back the compressor quit working. Stumped any ideas. P0651 on all data comes back as PCM issue, AC pressure switch issue, and a FTP sensor issue. P0452 comes back as a PCM issue, FTP issue, or a fuel tank wiring harness connector.

 

[Fless]

I'm sure Alldata would have these test procedures.

Here's a link to the test procedure for P0651:

P0651 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

P0452 test procedure:

P0452 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

 

[Angelo217]

I'm sure Alldata would have these test procedures.

Here's a link to the test procedure for P0651:

P0651 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

P0452 test procedure:

P0452 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

cool thanks for that. something just clicked, since they are "bussed" together inside of the pam, the FTP and ac pressure switch, I've gotten codes for the FTP sensor numerous times, and when I do the ac always seems to act up before or after I get a MIL for the fuel and pressure sensor, don't know if one going out effects the other, or if it is just something in the pam internally. feel like if the pam was going out I would have a multitude of issues outside of a lack of ac.

 

[Angelo217]

cool thanks for that. something just clicked, since they are "bussed" together inside of the pam, the FTP and ac pressure switch, I've gotten codes for the FTP sensor numerous times, and when I do the ac always seems to act up before or after I get a MIL for the fuel and pressure sensor, don't know if one going out effects the other, or if it is just something in the pam internally. feel like if the pam was going out I would have a multitude of issues outside of a lack of ac.

pam is PCM, autocorrect

 

[Angelo217]

I'm sure Alldata would have these test procedures.

Here's a link to the test procedure for P0651:

P0651 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

P0452 test procedure:

P0452 — 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Tahoe 4WD V8-5.3L VIN T.

charm.li

also I am assuming if I hook up my scan tool and read voltage of the ftp and ac pressure sensor that voltage should read as 5v? I believe I can recall reading the voltage off my scan tool for the FTP and it being like .14 or some stupid number.

 

[rockola1971]

Just look at your permissive inputs such as low pressure cutoff and hi pressure cutoff. Are they enabled during the no compressor clutch engage? Whats your pressures? Whats the ambient temp?