10 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH996 (2002) AC Stop Blowing Cool Air | Low Pressure Port Reads Higher than Normmal
Reported or suspected cause
why the compressor is not running
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
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Reported cause
Your problem is why the compressor is not running.
996 (2002) AC Stop Blowing Cool Air | Low Pressure Port Reads Higher than Normmal
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Leading evidence: 'why the compressor is not running' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'why the compressor is not running' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check pressures' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion · Original poster
Should the AC clutch circuit be bypassed to engage the compressor and check the pressures with the compressor running?
996 (2002) AC Stop Blowing Cool Air | Low Pressure Port Reads Higher than Normmal
Reconnect slide connector
Suggestion or failed attempt
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Suggestion · Original poster
Simple fix once found reconnecting the slide connector.
996 (2002) AC Stop Blowing Cool Air | Low Pressure Port Reads Higher than Normmal
Repair shop figure out why the compressor is not engaging
Suggestion or failed attempt
No successful repair reported for this finding.
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Reported fixes
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Unsuccessful attempts
1
Discussions
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Suggestion
have a repair shop figure out why the compressor is not engaging
996 (2002) AC Stop Blowing Cool Air | Low Pressure Port Reads Higher than Normmal
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10 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Hello. I am new to posting on Rennlist.
On my 2002 996 C4 the AC stopped blowing cold air on the first warm day of the year. Reading all the other AC troubleshooting and recharging posts, using a manifold gauge tool the low pressure port reads higher than normal and the high pressure port indicates lower than normal.
Port readings with engine idling and AC on max cool with fan on max:
Low pressure port: ~100 psi
High pressure port: ~90 psi
Other posts found describe the common condition where the low pressure port is lower than normal necessitating a recharge. Information about the low pressure port indicating higher than normal is not common.
Is this because of a blockage between the port and compressor? The clutch on the AC compressor is not engaging and fuses have been checked.
Should the AC clutch circuit be bypassed to engage the compressor and check the pressures with the compressor running? No R134 has been added. I am very careful to make sure proper procedures are followed to no damage anything.
It is now 90 degrees F in the Midwest US so would be really nice to fix the AC
Thank you in advance.
Oliver
2002 996 C4 convertible
Illinois
The pressure on both ports should be the same when the compressor is not running. 100 PSIG sounds about right with your ambient temp and you have enough pressure to engage the compressor. The difference you saw may be due to the error of the gauges.
Your problem is why the compressor is not running. You need to troubleshoot why it's not running. Whether the climate control is not commanding it or the power is interrupted somewhere.
Do you have Durametric? If memory serves, it can activate the compressor and that answer the above.
The power has to go through both a low pressure cutoff switch and the high pressure cutoff switch before it reaches the compressor so if either switch is bad, you won't get power to the compressor.
A harder problem is if the climate control does not command the compressor to turn on but let's wait for more troubleshooting on the easier parts first.
Another switch to consider is the one on the TB that kills the AC compressor under wide open throttle. Not sure which one does that. Good luck. One thing I would try is a 12v supply to jump the compressor to even see if it engages. You can even do that without the engine running. If it does then the trouble is one of the switches. If not then the electromagnetic clutch is faulty.
Thank you for the inputs and suggestions. Isn't there a low pressure cut-out switch that prevents the compressor clutch from engaging below certain pressures?
Thank you.
Yes but the threshold is way lower than 100PSI. However, that doesn't eliminate malfunctioning of the switch itself. You need at least a multimeter if not Durametric to diagnose it further.
Hi everyone. The 996 AC issues has been resolved. Troubleshooting backwards from the compressor clutch not engaging I found the clutch engagement wire connector was separated inside the insulation. Simple fix once found reconnecting the slide connector.
Thank you everyone for your help and inputs. Rennlist is really a great site!
