: Changed TPS on 95 STS d/t P020, now MIL & P080

12-24-05, 09:40 PM
I recently had to replace my TPS pigtail and sensor due to a ham handed but well intentioned shade tree mechanic's attempt to degrease and tune up the engine and fiddling with the air cleaner. I did this in response to several historic codes related to the TPS as well as a hard p022 and fast idling. That cleared out the P022 but I now have the P080 accompanied by the clicking of the ICM. Please tell me the proper procedure to relearn the TPS and idle. I tried disconnecting the grd to the battery for 60 seconds then letting it idle for 60 secs but did not clear the MIL or P080.

I appreciate it much, also, will this cause slipping of the transmission when kicked down when go to wide open throttle to blow out the carbon?

1995 STS with 240,000 (yeah, count the zeroes) miles, never opened the engine or transmission except to replace the A/B shift solenoids 8 months ago!



12-24-05, 10:15 PM
P020 (E020) ................................................. Open Fuel Pump Circuit
P080 (E080) .................................................. ..... Fuel System Rich
Check the FPR for leaks for the P080.
Don't recall the idle learn proceedure but it is in the archives somewhere if you do a search. That said, it will learn itself if you drive it for a few days.
ISC (idle speed control) motor is adjusted by pressing on the plunger with your finger til it retracts and then unplugging it when it bottoms out. Idle should drop to about 450. Adjust the plunger to .030 gap and plug it back in.

A clicking ICM (ignition control module) might be a bad coil.

12-25-05, 01:08 AM
Ranger, thanks for the reply, but I mistyped the first error code it should have been P022 not P020, a brain fart on my part!


12-25-05, 04:58 PM
P022 (E022) .................................................. Open TPS Signal [VCC]
That makes more sense based on what you said.

12-27-05, 02:30 AM
I have tried several different procedures to relearn the TPS and rid myself of the P080 code to no avail. Does anyone know how to do this specifically for a 95 STS Northstar?


Ken Seliga
12-27-05, 12:13 PM
And now a reading from the book, the 1995 Cadillac Service manual , page 6E-a-95 for the NorthStar 4.6l engine. P022 Open throttle postiton sensor.You need to know how to enter and use the the diagnostics. Key on . enter diagnostics.select pcm data port PD01( throttle position sensor and note value.-4 to 94 at part throttle means fault is NOT present. If the data is -14 to -5 you must repair the circuit mal-function before proceeding.
P080= TP sensor /Idle learn not complete.. To perform the idle learn procedure ..Turn ignition on, but engine not running
enter diagnostics
turn ignition off
wait at least 20 seconds
turn ignition on, engine not running
enter diagnostics
turn ignition off
wait 20 seconds
turn ignition on, engine not running
enter diagnostics
turn igniton off
wat 20 seconds
start the engine
allow the car to idle until coolant is 80 degees C ,then 5 minutes longer
apply the brakes and put tranaxle in drive
turn the climate control to off and idle 30 seconds more
turn the climate control to on and idle 30 seconds.
place the transaxle in park and turn igniton to off.

Try this procedure first..When my ISP motor got out of range ,the clicking I heard was the the Motor running in and out when the key was turned on or off as ISP tried to find the proper idle set....If this doesn't work let this thread know and i will enter the entire TP PROCEDURE..The book says the above TP sensor learn procedure should be performed any time
The TP sensor is replaced, The ISC motor is replaced, the Throttle body is replaced, the PCM is replaced or TP sensor learn values are over ridden using PS 13... try the procedure and see , if you live in a cold climate you will have to do this procedure again when the temp is over 55 F to compensate for the AC load...good luck

12-30-05, 09:59 AM
Hi Ken, Can you post the entire procedure, this didn't do it. I also replaced the Idle speed motor and cleaned the throttle body as well. Thanks a lot in advance.


12-30-05, 05:58 PM
P080 (E080) .................................................. ..... Fuel System Rich

Does this look better? P080 ...... TP Sensor/Idle Learn Not Complete

Ken Seliga
12-31-05, 05:06 PM
OK Here we go on the procedure..First the book says if the P080 code is not history after performing the previous idle learn procedure , then one or more of the following signals is at fault. Throttle positon switch, TP Sensor, Vehicle speed sensor, Transaxle range switch, power steering switch, or brake switch..I think we can safely stay with the throttle related components. First you cleaned the trottle body AND should have performed this procedure,clean throttle body with a clean shop towel and a cleaner NOT containing MEK.
1. Enter the diagnostics,
2. select PCM override PS13
3. press the "cooler" button on the climate control
4. Key OFF for 30 seconds( do NOT exit the diagnostics
5. perform the Idle /learn procedure

Replacing the Idle Speed (ISC) Controller
after replacement , perform the ISC check as listed below
1. Key "ON", engine off
2. enter diagnistics
3. no other codes should be present
4. Select pcm output cycling PO 07
5. The ISC plunger should extend and retract
6. Start the engine enter diagnostics
7. select PCM override PS 03
8. press the "cooler"to retract the ISC plunger
9. press the "Off" button and select PCM Data PD11
10. Note the engine RPM value
11. Below 700 rpm or stalls -Key "off". then Key "on". engine not running
12. enter diagnostics
13. select PCM overide PS03
14. press cooler button to retract ISC plunger
15. press "off" and select PCM Data PD01
16. wait 10 secondsthen record TPS Min value
17. Check to make sure throttle lever is contacting the minimum air screw
18. Press "warmer" button to extend the ISC plunger
19. wait 10 seconds , then record the TPS Max value
20. Subtract TPS Min value from TPS Max value and record.

Below 10
1. Adjust ISC plunger out by turning plunger counterclockwise

10 to 11
1. ISC is OK

Above 11
2. Adjust ISC plunger "in" by turnig clock wise

Perform above procedure untill value is 10 to 11

Perform IDLE/Learn procedure as outlined previously..

If this doesn't fix your P080 the you should check the TP sensor output voltage, The tp sensor is just a potentiometer where the center wiper voltage should increase and decrease as the throttle is opened and closed.

I told you this was complicated , there are no other adjustments to the 4.6 liter fuel system you can make to fix this P080, that I know of, anyway..Let me know how this works..

01-01-06, 02:50 AM
Thanks Ken for the procedure. I also replaced the plugs, it had Bosch plugs now AC Delco and autozone sparkplug wires. I found that the high tension pin for plug 4 on the 2nd coil pack in had been rusting so I put a new one in but it did the engine still is doing the same thing.I cleaned the EGR valve, throttle body and replaced the ICM as mentoned earlier, now I am still getting the P080 code current but also, the car idles pretty well during the warm up for the TPS relearning procedure but after it warms up the idle sits around 700 rpm and occasionally "surges" briefly about 50 to 100 rpm and eventually start getting a popping intermittently in the exhaust (sounds like a small firecracker in a long pipe, not a loud backfire through the exhaust sound) drivability is poor also, any time accelerate with or without load get popping sound also if pulling up a hill etc. I had removed the throttle body to replace the ICM and resealed it with a thin film of RTV and was reusing the old O-ring which had expanded, probably due to the carb cleaner so I cut it and rtv'ed the ends together, it was a good but joint and I put a thin coat of rtv on the mating surface. I was monitoring the data for the TPS and it varies with throttle changes, ICM is 5.4 retracted and 16.7 extended so I need to turn in the screw a little bit more, I had set it fully retracted until there was some spring action in the screw and not bottomed out by throttle return spring tension. I also checked the FPR by looking for seepage at vacuum port while running, although for only a couple of seconds and it stayed dry. I cannot hear any vacuum leaks. I will try the other procedure tomorrow, and I appreciate what you have done for me so far. I would appreciate further any assistance you may offer on the new "mechanics tracks" listed here, maybe I am as ham handed as my friend (ha ha). I have both volumes of the GM service manual on order but haven't received it yet. I am 52 years old and have overhauled MGs and motorcycles and have done my own work for decades so I don't feel I am a complete novice and professionally I am a field service technician for an industrial laser esposure device. Just mentioning it so you know a little about my experience, obviously I am not an expert on late model vehicles, but rather proficient with points and rotor dinosaurs.

Also, the only code setting is P080 always current, no other codes current or historical. I have noticed references to P080 being either "fuel system rich" or "tps relearning not completed", do you know which actually applies to a '95 STS.

This car was running very well and the only prolem was occasional transmission slip in going WOT and forcing it to do a hard downshift until my friend tried to tune it up, It has been downhill ever since and I suspect the culprit is going to be a simple and in retrospect obvious issue.

Take care and look forward to your reply and anyone else's concerning my downward spiraling experience attempting to fix it.

Jim West:banghead:

Ken Seliga
01-02-06, 03:47 PM
Well Jim, I'm guessing you are right and the problem is something simple..Good move on buying the original Caddy manuals( From Helm?) I have yet to find a mistake in the well written procedures in the books..Just be a little careful as the manuals cover both the 4.6L and the 4.9L and one can find oneself in the wrong section quite easily. I am thinking of an old mechanics trick used to find leaky intake manifolds, I don't know if it will work for you but it might be worth a try. We used to spray "Instant Start," (aerosol can) around the intake manifold and if the engine speeded up the you know you had a leak..You might try spraying instant start around your throttle body and see what happens..There is also an old wives tales that one shouldn't use RTV in any fuel/air intake systems as it might destroy the oxygen sensors...that of course would give you a different error code so you are OK there...still I can't help but think your problem is in something you assembled..P080 is definitely ...Idle learn procedure incomplete.
You mentioned you restored MG's, I didn't know anyone ever restored /fixed MG"S , I thought they just parked them in the garage when they quit running.
The North Star is a great engine requiring lots of nit picky type of work..Good Luck ..You do know that there is a re-call to replace (for free) the vinyl Fuel rail with stainless steel fuel rail ..Caddy replaced mne and it didn't cost me a cent...

01-02-06, 04:17 PM
I believe I have read it a few times that the throttle body o-ring should not be reused. You might want to look into that. I know you put time into splicing and reattaching your's, but that might not have been good enough.

About what Ken mentioned about intake vac leaks...I was having a somewhat similar problem on mine. I would hear an intermittent whistle and idle would jump sporadically. I located the leak with a stethoscope. Checked the torque on the intake and it was less than 5ft/lb. It was suppose to be 7.5ft/lb (IIRC). Anyways, I retorqued and now it is fine. You might want to check yours also.

01-18-06, 05:00 PM
Well, here goes,

The intermittent backfiring was crossed plug wires(1 & 5), the reason I couldn't relearn idle was the new throttle position sensor was intermittently bad and after changing the ICS it went bad completely. Now it is running well except for a high rpm miss (>3200rpm) which I figure is probably plug wire routing. Thanks to all that contributed to this thread.

Jim:woohoo: :cheers:

Ken Seliga
01-28-06, 04:18 PM
Well Mr Jim West..you are an honest man to admit to the two crossed plug wires//I might have been tempted to make up some theory about the phases of moon and witches...Glad you found your problem, I admit I was curious when we hadn't heard from you for a while. Like I said North*'s have their problems..."In the valley of the blind the one eyed man is king".