QuestionHow do I clear codes?
As to hose to MAP Sensor, is this the one from the brake booster to the MAP Sensor mounted on the brake booster? This sensor was the one replaced.
Thanks again,
Don
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Thanks, Now I feel we are getting somewhere. How about hold RPM's above idle to 1200 to 1500 RPM's with no A/C and no Power Steering engaged should the RPM's still fluctuate up and down 500 RPM's?
Also after shop removed history codes I using onboard computer through climate control reviewed system and find stored codes in history:
T072 - P032 - P071 again.
Thanks,
Don
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Question -
Yes! it does it with A/C on or off. As to windshield heater code...I most likely misquoted the 90 code. It was not the windshield heater code, but one in the low 90 that pertained to temporary engine cough or stalled, not sure of correct wording but meaning the same.
It does not have a miss in the engine at idle or any speeds indicating not ignition. Just engine deceleration and acceleration. Noticed that when in Park and rev engine to 1500 RPM's turning steering wheel decreases RPM's 500+ RPM's and stays there while pressure on power steering pump, does not increase to compensate for power steering. Yet it is perfectly smooth at Idle (700 to 1000 RPM's). Could it be possible that the new computer or chip is bad or not communicating with what ever tells the engine to increase engine RPM under loads at lower RPM's? The car runs perfectly down the road at highway speeds and with and without cruise control with tach needle smooth. Other than in Park the only movement in tach is at speeds above idle to 28 MPH, shows slight movement or fluctuation, +or- 100RPM's. I don't think it is a vacuum leak as technician said he checked for vacuum leak and it is steady and good. I just don't know what to do next.
Thanks,
Don
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Question -
Well, I have done that on a couple occasions and they say they can't find anything if the the computer does not leave any codes. All they have to analyze is their test computer read out device. And this is a local Cadillac dealership. What has happend to the days when a mechanic could test things other than total reliablity on some computer device. They say until it stops running or leaves a code they are at a loss. So much for computers if one has to wait until engine is inoperable before warning of faulty part.
I was hoping you had some suggestion for me to tell them. Originally the code 92 and 71 was what I remembered. But one was intermitten MAP senser reading and the other was Engine coughed or stalled temporarily. Now leaves none but does the same things.
Thanks for your time,
Don
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My 1994 Cad Eldorado with northstar engine began surging at low speeds in town. Took it to local Cad dealer. They cleaned Trottle Body and then said they thought it was a bad Computer or ISC Motor and said 95% sure Computer. Installed new computer with new Chip. Occasionally at slow speeds it will seem to stall and then throttle advances itself and sometime will stall. Also when in Park rev engine rpm to 1500 RPM and the rpms drop 500 to 600 RPM and then advance up and then back down consistantly up and down. sometimes even turning steering wheel cause it to drop 500 RPM's. The Cadillac mechanics don't know what is causing this and think this is normal in Park? Never leaves a code. Once when it stalled it left two in the history 71 and 92 I believe. One mentioned MAP sensor and the other engine coughed or stalled.
Answer -
71 is a MAP circuit sensor problem and 92 is a heated windshield circuit problem.
You need to CLEAR these 2 codes from the computer and see if they come back again.
Hello,
The garage cleared both codes and yet the same problem exists and now leaves no codes. Should not the RPM's when in neutral and rev to 1500 to 1800 RPM stay constant and not start irratic up and down RPM's, Drop 500 RPM's down and back up and continue to do this?
These problems still exist after removal of codes and yet leaves not code at all. It still Occasionally at slow speeds will seem to stall briefly or cough and then throttle advances itself and yet sometimes will stall. Also when in Park rev engine rpm to 1500 RPM and the RPM's drop 500 to 600 RPM and then advance up and then back down consistantly up and down. Sometimes while in Park even turning steering wheel will cause it to drop 500 RPM's.
1994 Cadillac Eldorado-4.6L 32 valve Northstar V8
Work done: Cad Dealer replaced Computer and PCM chip with latest upgrade. Cleaned Trottle Body and Replaced Power Brake Booster MAP sensor.
Thanks,
Don
Answer -
There are just to mny possibilities as what is causing this problem. You need to have a technician perform some tests on the vehicle.
Answer -
I would spray some carb cleaner around the intake manifold and see if the rpm's increase as this would be cause of a vacuum leak.
Could be an intermittent fault in:
Excessive carbon buildup within the EGR system.
Excessive buildup of contamination around the throttle plate area.
ignition control module.
one of the ignition coil packs.
low fuel pressure.
idle speed control motor.
fuel contamination (water).
broken or loose vacuum lines on the engine.
worn out spark plug wires.
A problem with the heated windshield circuitry as it may be turning itself ON and OFF.
Does this problem still occur if you turn OFF the AC ?. If the freon level is low it can cause the A/C to constantly cycle ON and OFF causing your irratic idle.
Answer -
P095 = Engine stall detected ?.
To test the power steering pressure switch:
Have engine running at idle speed, Turn steering wheel to full left turn and idle speed should increase slightly. If engine speed is above 1000 rpm's and you turn the steering wheel the pressure switch is not used and the engine speed will drop 500 to 600 rpm's due to the load on the engine due to the pressure in the power steering system.
The power steering pressure switch ONLY is operable at idle speeds.
If your holding the engine speed up around 1500 and you turn the steering wheel the engine speed will drop as this is normal.
Answer -
T072 = serial data link fault in the traction control system.
P032 = open in the map sensor circuit.
P071 = intermittent map sensor signal failure.
The T072 would have nothing to do with your problem.
The other 2 intermittent faults would cause an erratic speed control.
You need to CLEAR the P0 codes from the computer and drive the car and see if they come back.
Check the hose that is connected to the MAP sensor for feeling real soft as when they get soft they tend to suck the hose flat and this shuts off the vacuum to the sensor. If it feels extremly soft and or has a crack in it replace the hose.
Holding the engine rpm's at approx 1500 and above will also cause the EGR valve to flutter open and closed due to no LOAD on the engine as when you are actually driving the vehicle on the road and this EGR flutter would cause the rpm's to go up and down and this wouldbe considered normal.
Answer1. Ignition ON. Engine OFF.
2. Simultaneously push and hold the OFF and WARMER buttons for 3 seconds and release them.
3. You will see the 3 codes appear and then you will see PCM?.
4. Push and release the HI button and you will see PCM DATA?.
5. Keep pushing and releasing the LO button until you see PCM CLEAR CODES?
6. Push and release the HI button and you will see PCM CODES CLEAR?
7. Wait 3 seconds and turn OFF the ignition.
8. This will clear the 2 P0 codes.
