MIL is On, and DTC P0121 is Set
File In Section: 6E - Engine Fuel & EmissionBulletin 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 power steering 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 not 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.
Important:
There are three methods for programming a PCM:
1. Direct Programming. The vehicle is directly connected via the Data Link Connector (DLC) to the Dealer's/Retailer's Techline equipment. (T-20 Plus, T-50 and T-60 only.) Vehicle must be present.
2. Remote Programming. The new program is downloaded into the dealer's/retailer's scan tool and then downloaded into the vehicle from the scan tool via the DLC. Tech 2 required. Vehicle must be present.
3. Off-Car Programming. A PCM may be programmed while removed from the vehicle by using the off-board programming adapter (OBPA), P/N J 41207-b. This adapter can be connected to either the Techline Terminal for direct programming or to the scan tool for remote programming. Not necessary for the vehicle to be present.
Refer to the appropriate Service Manual or Techline Information for more detailed instructions.
Important:
Do not attempt to order the calibrations from GMSPO. The calibrations are programmed into the vehicle's PCM via a Techline Tool Device.
Parts Information
Warranty Information
Labor Operation Description Time
J6355 On-Car Prom Use Published
Reprogramming Labor Operation
Flash E Prom Time
J6352 Off-Car Prom Use Published
Reprogramming Labor Operation
Flash E Prom Time