P0121 Trouble code "range/performance"

[Prof_h]

Hi Everyone,
'97 PA 3800 series II K 155,000mi
I had this P0121 code on the OBD reader and thought I solved the problem when I replaced the TPS. Well, I drove about 250miles and the SES came on with same code as before. I reset the SES drove about 50 miles and then it came on again. I've been reading and viewing a lot of posts about checking the voltage from the various wires that come out of the TPS connector, but I'm still a little nervous on if that is even the problem. The car runs great, no hesitation, no stalling, nothing. The SES light came on each time at the first start of the morning. Car sat all night, then when I started it up, bam, the SES light and P0121 code. Don't think the weather is a problem but we are dry, 60's to 80's, you know that lovely Florida fall weather. Sorry, had to rub it in.
Any suggestions?
Wendy

[Tech II]

Could be the connectors in the harness connector or could have a broken wire inside the insulation, causing an intermittant problem.....

Only way to know for sure is to open/close the throttle plate while moving the harness and watching the data on a scan tool....

There is also the possibility that there is a reflash to correct the problem...

[Prof_h]

I understand I have to check the wiring with a scan tool along with moving the throttle, but what do you mean about "reflash"?
W

[Prof_h]

Just checked all of the voltages coming out of the wires from the TPS. They all check out okay. My friend suggested cleaning the baffle inside the throttle body. Guess I'll do that next. Hope that keeps the SES light off!
W

[Tech II]

If the Throttle plate is sticking, that might help....

Googled P0121 and found this:

There is a service bulletin for that. It will involve flashing, (reprogramming) the PCM calibrations. Here is what it states;


MIL is On, and DTC P0121 is SetNotesFile In Section: 6E - Engine Fuel & Emission
Bulletin No.: 67-65-32
Date: October, 1996
Subject:
Malfunction Indicator Lamp (MIL) Illuminated; Diagnostic Trouble Code (DTC) P0121 Stored (Flash with New Calibration DO NOT Replace any components)
Models:
1997 Buick LeSabre, Riviera
1997 Oldsmobile Eighty Eight, LSS, Regency
1997 Pontiac Bonneville, Grand Prix with 3800 Series II (VIN K - RPO L36)
Condition
Some 1997 vehicles built prior to September 15, 1996 may illuminate the Malfunction Indicator lamp and store Diagnostic Trouble Code P0121 in the Powertrain Control Module (PCM).
Cause
Current DTC P0121 Diagnostic Calibration is too sensitive to high engine loads at idle. The high engine loads can be due to [COLOR=green !important][COLOR=green !important]power [COLOR=green !important]steering[/color][/color] cramp, high A/C head pressure, and high electrical demands.
Correction
Check calibration scan identification (ID) number utilizing a scan tool device. Re-flash with updated calibration if scan ID number is XXXXX as recent as the calibrations listed in the parts section of this bulletin. If the vehicle already has the most recent calibration, then refer to the appropriate service repair manual to diagnose and repair for DTC P0121. Test drive the vehicle after repair to ensure that the condition has been corrected. The new calibrations are available beginning with 1996 CD Disc 17 from GM Service Technology Group.








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