MACS Service Reports - 2016 - MAR7

Steve Schaeber

down position along the high pressure line and below the
upper radiator support. It basically says that the original
wiring harness leads to this sensor were not made long
enough, and that over time as the engine mounts wear
out, the extended back and forth rocking of the engine
would pull on these wires to the point where they could
break. There is a service kit available from GM with a new
connector and longer wire leads to correct the problem,
and while it's similar to what we did to fix this car, it's
not exactly the same. From what we can tell, the wires we
repaired were damaged due to the position of the suction
line, sometimes resting against the high side sensor, and
sometimes against the connector. See Figure 17. But it's
possible the short length of the wires also had something

Steve Schaeber

Steve Schaeber

Figure 13: Separating the connector from the PCM is a good idea when
checking for continuity across sensor wires. Notice the pin out chart showing terminal numbers and functions.

Figure 16: After completing the repair, we used the scan tool once again
to double check our work. A/C HI-SIDE (V) is now showing 1.39 volts,
and A/C HI-SIDE (PSI) reads 116 with both the engine and A/C running.
Notice also the A/C REQUEST is being received by the PCM, which commands the A/C RELAY to ON, activating the compressor.

Steve Schaeber

Figure 14: A small paperclip can be used to make contact with the female
pin inside a PCM connector, so long as it doesn't damage the terminal. We
used our DMM's black lead to probe this end of the wire.

Steve Schaeber

Figure 15: With an auto-ranging DMM set to measure ohms (Ω), we used
the red lead to probe the sensor connector. "0L" on the display (sometimes
referred to as "out of limits") indicates an open circuit, or lack of continuity. In our case, it's a broken wire.

I've left out one crucial tip and that's to always check
service information for any possible TSBs that may be out
there. We didn't look until after we started diagnosing this
system, and I'm not sure if it would have helped either
way. But not surprisingly GM has issued a TSB (02-01-38003) for a very similar problem on several models with
the high pressure transducer that's mounted in an upside-

March 2016

Figure 17: We suspect this suction hose had something to do with the
damaged sensor wires. It appears to have been resting against the sensor
and/or connector. Even though we replaced the damaged leads, we tied
this hose back slightly to relieve the pressure, and hopefully to avoid a
repeat failure and eventual comeback.

7

MACS Service Reports



Table of Contents for the Digital Edition of MACS Service Reports - 2016

MACS Service Reports - 2016 - JAN1
MACS Service Reports - 2016 - JAN2
MACS Service Reports - 2016 - JAN3
MACS Service Reports - 2016 - JAN4
MACS Service Reports - 2016 - JAN5
MACS Service Reports - 2016 - JAN6
MACS Service Reports - 2016 - JAN7
MACS Service Reports - 2016 - JAN8
MACS Service Reports - 2016 - FEB1
MACS Service Reports - 2016 - FEB2
MACS Service Reports - 2016 - FEB3
MACS Service Reports - 2016 - FEB4
MACS Service Reports - 2016 - FEB5
MACS Service Reports - 2016 - FEB6
MACS Service Reports - 2016 - FEB7
MACS Service Reports - 2016 - FEB8
MACS Service Reports - 2016 - MAR1
MACS Service Reports - 2016 - MAR2
MACS Service Reports - 2016 - MAR3
MACS Service Reports - 2016 - MAR4
MACS Service Reports - 2016 - MAR5
MACS Service Reports - 2016 - MAR6
MACS Service Reports - 2016 - MAR7
MACS Service Reports - 2016 - MAR8
MACS Service Reports - 2016 - APR1
MACS Service Reports - 2016 - APR2
MACS Service Reports - 2016 - APR3
MACS Service Reports - 2016 - APR4
MACS Service Reports - 2016 - APR5
MACS Service Reports - 2016 - APR6
MACS Service Reports - 2016 - APR7
MACS Service Reports - 2016 - APR8
MACS Service Reports - 2016 - MAY1
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MACS Service Reports - 2016 - MAY3
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MACS Service Reports - 2016 - MAY5
MACS Service Reports - 2016 - MAY6
MACS Service Reports - 2016 - MAY7
MACS Service Reports - 2016 - MAY8
MACS Service Reports - 2016 - JUN1
MACS Service Reports - 2016 - JUN2
MACS Service Reports - 2016 - JUN3
MACS Service Reports - 2016 - JUN4
MACS Service Reports - 2016 - JUN5
MACS Service Reports - 2016 - JUN6
MACS Service Reports - 2016 - JUN7
MACS Service Reports - 2016 - JUN8
MACS Service Reports - 2016 - JUL1
MACS Service Reports - 2016 - JUL2
MACS Service Reports - 2016 - JUL3
MACS Service Reports - 2016 - JUL4
MACS Service Reports - 2016 - JUL5
MACS Service Reports - 2016 - JUL6
MACS Service Reports - 2016 - JUL7
MACS Service Reports - 2016 - JUL8
MACS Service Reports - 2016 - AUG1
MACS Service Reports - 2016 - AUG2
MACS Service Reports - 2016 - AUG3
MACS Service Reports - 2016 - AUG4
MACS Service Reports - 2016 - AUG5
MACS Service Reports - 2016 - AUG6
MACS Service Reports - 2016 - AUG7
MACS Service Reports - 2016 - AUG8
MACS Service Reports - 2016 - SEP1
MACS Service Reports - 2016 - SEP2
MACS Service Reports - 2016 - SEP3
MACS Service Reports - 2016 - SEP4
MACS Service Reports - 2016 - SEP5
MACS Service Reports - 2016 - SEP6
MACS Service Reports - 2016 - SEP7
MACS Service Reports - 2016 - SEP8
MACS Service Reports - 2016 - OCT1
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MACS Service Reports - 2016 - OCT3
MACS Service Reports - 2016 - OCT4
MACS Service Reports - 2016 - OCT5
MACS Service Reports - 2016 - OCT6
MACS Service Reports - 2016 - OCT7
MACS Service Reports - 2016 - OCT8
MACS Service Reports - 2016 - NOV1
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MACS Service Reports - 2016 - NOV3
MACS Service Reports - 2016 - NOV4
MACS Service Reports - 2016 - NOV5
MACS Service Reports - 2016 - NOV6
MACS Service Reports - 2016 - NOV7
MACS Service Reports - 2016 - NOV8
MACS Service Reports - 2016 - DEC1
MACS Service Reports - 2016 - DEC2
MACS Service Reports - 2016 - DEC3
MACS Service Reports - 2016 - DEC4
MACS Service Reports - 2016 - DEC5
MACS Service Reports - 2016 - DEC6
MACS Service Reports - 2016 - DEC7
MACS Service Reports - 2016 - DEC8
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