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Pontiac Bonneville General Maintenance and Repair



  • mshmsh Posts: 3
    I have a 2001 Bonneville, 3.8 series II, with 86,000 miles on it. The transmission seems to shift hard from first to second, and second to third, even into overdrive there is a hard shift. It is not smooth like is should be. There is always a jerk into the next gear. Any help would be appreciated, on what it could be. Thanks.
  • mshmsh Posts: 3
    I also have a problem with my 2001 Bonneville's gas gauge. It always reads full. It seems to stay on full all the time. No matter how much gas it has in it. Stays on full. Would this be a bad sending unit? Any info would be appreciated. Thanks
  • alcanalcan Posts: 2,550
    This TSB from GM might apply. It addresses problems with the pressure control solenoid in the transaxle:

    Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly) #00-07-30-002B - (Jul 19, 2002)

    1997-1999 Buick Riviera
    1997-2002 Buick Park Avenue
    1998-2002 Buick LeSabre
    1999-2002 Buick Regal
    2000-2002 Buick Century
    2002 Buick Rendezvous
    1997-2001 Chevrolet Lumina
    1997-2002 Chevrolet Monte Carlo
    1999-2002 Chevrolet Venture
    2000-2002 Chevrolet Impala
    1997- 1999 Oldsmobile Eighty Eight
    1997-2002 Oldsmobile Silhouette
    1998-2002 Oldsmobile Intrigue
    2001-2002 Oldsmobile Aurora (3.5L)
    1997-2002 Pontiac Bonneville, Grand Prix
    1999-2002 Pontiac Transport/Montana
    2001-2002 Pontiac Aztek
    with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76)

    This bulletin is being revised to add additional models and model years. Please discard Corporate Bulletin Number 00-07-30-002A (Section --Automatic Transmission).

    Some owners of the above vehicles with a Hydra-Matic 4T65-E transaxle may comment on harsh upshifts or harsh garage shifts, soft shifts, shudders on hard acceleration, or shifts erratic. These conditions may appear intermittently or set a DTC P1811 or P0748. During diagnosis, a low or high line pressure (actual versus desired) may be observed.

    The above condition may be due to any one of the following which may affect line pressure output:

    Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind.
    Sediment in the valve body, causing the torque signal regulator valve to stick.
    Incorrect transaxle oil level.


    Any of the above conditions may be intermittent, therefore, this test should be performed at least three times.

    Refer to the Line Pressure Check Procedure in SI, along with the Line Pressure Specification Table below, to determine if actual versus desired pressures are within the values specified. The Scan Tool is only able to control the PC solenoid valve in PARK and NEUTRAL with the vehicle stopped. This protects the clutches from extremely high or low pressures in DRIVE or REVERSE ranges.

    Yadda, yadda, yadda........
  • alcanalcan Posts: 2,550
    Probably the sending unit but could also be a wiring or instrument panel cluster problem. Step #1 in the factory manual diagnostic routine is to verify operation of the instrument cluster. A Tech2 scan tool (GM dealer) is required to diagnose it properly.
  • henrylhenryl Posts: 15
    I have a 96 Bonnie with 108,000 miles on it and im having a cooling problem. The A/C does not blow hard or cold it starts to work better when Im on the freeway. so city driving it it not very cool the thermostat is on 60 and the fan is on high but its barley blowing any air. Its electroinc controled. I hear something like a vacumm leak from the pass sid footwell. Ive spent quite a bit of money on the A/C
    it has been fully charged anf the controller is brand new. Whats next!
  • mshmsh Posts: 3
    Thanks for the info. Do you know where the Pressure Control Solenoid is located? Is it inside the transmission?
  • alcanalcan Posts: 2,550
    It's one of the six solenoids attached to the valve body, under the end cover of the transaxle.
  • henrylhenryl Posts: 15
    I have a 96 Bonnie with 108,000 miles on it and im having a cooling problem. The A/C does not blow hard or cold it starts to work better when Im on the freeway. so city driving it it not very cool the thermostat is on 60 and the fan is on high but its barley blowing any air. Its electroinc controled. I hear something like a vacumm leak from the pass sid footwell. Ive spent quite a bit of money on the A/C
    it has been fully charged anf the controller is brand new. Whats next!
    I took it to my local AC shop they are telling me the compressor, accumlator and the expansion valve need to be replaced. Does this sound correct the quote for the work 900-1100 bucks.
  • alcanalcan Posts: 2,550
    If the compressor has failed, then the quote is about right. Reman compressors usually come with the warning that the compressor is not covered by warranty unless the accumulator/dryer is also changed. Also, debris from the compressor gets into the system and requires a system flush and expansion valve replacement.
  • bcorsobcorso Posts: 3
    To me it sounds like a blockage of your vents in some way. If the fan is on high, and little to no airflow, that sends a big red flag something is blocking the airflow from your fan. I would pursue that LONG before dumping a ton of money into something that probably wont fix the problem.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,045
    You may have a system comparable to my LeSabre. I had a slow movement of the various vacuum motors that pull the vanes inside the box that directs all the air under the dash.
    If you hear a vacuum leak under the right side, that could be the reason there not much happening. The vacuum line comes in at the right side from the passenger compartment. Then it goes to a switching device that's electrically controlled on the automatic air system. From there hoses come out to 5 or 6 vacuum motors that pull the vanes. Any of those vacuum lines could be damaged.
    You have to take off 3 or 4 little screws under the dash above the passenger's feet to get up under there. Then you need to take off four or 5 screws that hold the glovebox up. You need to be able to see through that opening to see the vacuum lines coming in.
    I have a service manual so it's not as intimidating as it sounds to me.

    I moved around the vacuum lines and tried to disconnect the main one. The system started working better, so one of those lines wasn't connected well or something. The dealer had been into that area with a fan motor controller problem a couple years ago and the air never seemed to blow out as well after that.

    IF you have no vacuum to the controller box under there, the air should be coming out the defrost vents. That's what the system does when there's no vacuum to control it. Try feeling up there to see if you're getting air when you first start the car. Then see if it tries to move the air to other output after a minute or more of running the motor.
  • henrylhenryl Posts: 15
    Thanks for all the advice It was tracked down to the main computer since it was the diaphram was tore and the lines were brittle. All the vaccum line from the a/c go to there. That is why it wasnt blowing hard till I got on the freeway. At idle speed the vaccum was low. Next problem a/c not cold. When the system was evacuated. The revious tech, put 1-1 1/2 oz of pag oil anf way too much freon. The gauges said 300psi high side and 36psi low side. Got that fixed now colder, but im still debating if i should replace the computer and the lines because its still going to be 900-1000 dollars. Its been to 4 a/c shops and every one told me something diffrent. The other shops told me what it was and when i could drop it off. This guy actually walked me through it and showed me the problem and explained it. Man it sure is hard to find a good tech. Also didnt charge to look at it. Thanks Guys
  • I have a 2001 Bonneville that has developed paint bubbling along the front edge of the hood. I am told this is aluminum corrosion and it is covered under a GM bulletin ID#1230005 and is referred to as premature aluminum hood corrosion/blistering. This document lists all makes & models of GM vehicles experiancing the same problem. It also appears on Buicks, Chevs, Olds. I experienced the problem at about 75000 miles and,like a darn fool, didn't complain about it until 92000 miles. I was told that I should call 1.800.GMcares and I soon found out GM does not care. I maintained it was the same as rust thru and should be covered for 6 yrs. or 100K miles. They say 36000 miles is all they will cover. I have since found out that in Wisconsin they are covering it to 100K but I live in Michigan and no such luck here. Anyone else experience this prob?
  • I have a '93 Bonneville SE with 137K miles on it.
    Lately the car surges while maintaining a constant speed or under slight acceleration anywhere from 40 to 80 mph. It seems as though the transmission can't decide which gear to be in.
    I also notice a clunking metal sound while the car is in neutral or park and the revs are above 1200 RPM (such as after a cold start). I can also demonstrate the clunk if I increase the revs from idle while in neutral or park. I have seen some other posts related to these problems and am wondering if there is anything a non-mechanic can do?
    Thanks for any help.
  • This is my first post here so please bare with me. My wifes 98 bonneville's security light stays on and won't go off. Now at low speeds the cars chime goes off and the engine dies. You have to come to a complete stop and put the car in park to restart the engine. Somebody told me the chip in my key was bad. I have the same problem with 2 keys. Anybody have any suggestions?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,045
    Had mine come on in a 93 LeSabre. The wiring to the ignition where the key chip is sensed starts to break. It's multiple small wires and as they break, the resistance of the wire changes.

    The security light comes on. If the wire breaks completely, then the car won't start because the chip can not be sensed at all.

    I was hoping in 98 that flexing and breaking problem had been fixed. But the car shouldn't die from that once it's running, as I understand the setup.
  • I also have a 2002 ssei that also has major issues with water leaks. All started with windshield to trunk now to water in floorboards. Dealership has had my car 24 times due to leaking and other issues.
    Finally got windshield & trunk fixed but not the floor. I was looking for someone who had or has the same problems as I have had with their car. Mine comes up under the car when you are driving in the rain.
  • idntnvuidntnvu Posts: 251
    Wow, finally, after all this time someone else with a '93 signs on!
    My sister's (formerly my mom's) '93 SSEi has never had that sort of problem, but, I do know for a fact that there were many transmission failures in the '92-'94 Bonnevilles. A friend of mine had an SSE and had the transmission replaced somewhere around 150k miles. My sister's has 117k on it.
    As for the clunking, this car used to pop and "backfire" sometimes when you reved it up to a certain rpm, but I think it had something to do with a limiter to keep it from over-reving.

    As for leaks, I think thats been a problem with Bonnevilles dating back to the '92 generation. the '93 we had leaked quite a bit, and my dad took some silicone and filled in around all the doors, but water would still come in, presumably from the sunroof. I had a problem with a '98 Suzuki of water coming up through the floor, and it turned out it was a plastic cap that was supposed to be filling a hole in the floorboard had come out and was allowing water to come in. Especially a pain when you go through a car wash.
  • I have the same problem which I posted in past I think it was somewhere between post 1250-1300. I still have the shuttering at highway speeds I've been told its the Torque converter clutch and solinoid valve which comes down to I need to get transmission rebuilt.One thing that has helped was Lucas transmission treatment fluid.
  • I have a 1996 pontiac bonneville Se with 178303 miles. I been losing coolant about a half gallon every 4 days unknown if head gasket leak or dripping it out. The only drips i've seen is on the bottom of the back firewall where A/C condensation comes out but seems like a lot more then normal and not the red dexcool color.I cleaned the engine with Gunk engine cleaner and water hose the next day I had my check engine light come on which I was told was a code for Misfire cyclinder#6 and a loud ticking(like fuel injector but very loud). My mechanic thinks its a collapse lifter. As the engine was running the ticking stopped but engine light still on.I changed the #6 coil pack and engine light went off.Help any Ideas will be appreaciated,thanks.
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