OBD II DTC P1404 (REFLASH VCM). Chevrolet Chevy C Pickup

REVISION: 09/03/98 DIVS INVL 1 3 5 7

THIS BULLETIN IS BEING REVISED TO CORRECT APPLICATION INFORMATION FOR CALIBRATION P/N'S 09364726 AND 09364733 AND ADD THE ISUZU HOMBRE MODEL. PLEASE DISCARD CORPORATE BULLETIN NUMBER 86-65-03 (SECTION 6E - ENGINE FUEL & EMISSION). ______________________________________________________________________

SUBJECT: OBD II DIAGNOSTIC TROUBLE CODE (DTC) P1404 (REFLASH VCM)

MODELS: 1998-*99 CHEVROLET AND GMC C/K, M/L, S/T**, G, P MODELS 1998 OLDSMOBILE BRAVADA 1998 ISUZU HOMBRE WITH 4.3L, 5.0L, 5.7L OR 7.4L ENGINE (VINS X, W, M, R, J - RPOS LF6, L35, L30, L31, L29)

*(C/K, G WITH RPO ZK3) **(DOES NOT INCLUDE RPO ZN4)

CONDITION:

SOME VEHICLES MAY SET A FALSE OBD II DTC P1404.

CAUSE:

ELECTRONIC NOISE IN THE VEHICLE MAY CREATE MOMENTARY FALSE "LOW" EXHAUST GAS RECIRCULATION (EGR) PINTLE POSITION FEEDBACK SIGNAL VALUES. SEVERE OCCURRENCES MAY CAUSE THE VEHICLE CONTROL MODULE (VCM) TO SET A P1404 DTC BECAUSE THE VCM PERCEIVES THAT THE EGR VALVE IS STUCK OPEN.

CORRECTION:

1. USING THE TECH 2 SCAN TOOL, EXERCISE THE EGR VALVE AND VERIFY THE VALVE'S ACTUAL AND DESIRED POSITION TRACK.

2. FOLLOWING STEPS 1, 2 AND 3 OF THE STRATEGY BASED DIAGNOSTICS, DETERMINE IF THE VEHICLE HAS AN ACTUAL EGR VALVE CONDITION. IF THERE IS A VALVE CONDITION, PERFORM THE APPROPRIATE REPAIR PROCEDURES.

3. FINALLY, REFLASH THE VCM WITH THE NEW SOFTWARE AND CORRESPONDING CALIBRATIONS LISTED BELOW. THESE NEW CALIBRATIONS ARE DESIGNED TO MAKE THE DTC LESS SUSCEPTIBLE TO NOISE.

SOFTWARE INFORMATION

OLD P/N NEW P/N APPLICATION ------- ------- ----------- 16263425 09365095 ALL VEHICLES WITH RPO'S L35, L31, L30, L29

NEW ENGINE CALIBRATIONS

OLD P/N NEW P/N APPLICATION ------- ------- ----------- 16267584 16249499 M/L WITH L35&M30&NF2&NM8 16249477 09360060 M WITH L35&M30&NF2/NA3-NN8/NM8 16249478 09360061 L WITH L35&M30&NF2/NA3-NN8/NM8 16249479 09360062 M WITH L35&M30&NB7 16249480 09360063 L WITH L35&M30&NB7/NC1 16249481 09360064 L WITH L35&M30&NF2&NN8 16249482 09360065 M WITH L35&M30&NF2&NN8 16249483 09360066 G WITH L35&M30&NF2/NB6 16249497 09360067 G WITH L35&M30&NF2/NB6 16249485 09360069 G WITH L35&MT1&NF2 16249498 09360070 G WITH L35&MT1&NF2 16249500 09360071 G (CUTAWAY) WITH L35&MT1&NF2 (W/P TRUCK PURGE RATES) 09350941 09364745 C/K WITH L35/LF6&MG5&NN8 09350945 09364746 C/K WITH L35/LF6&MG5-NN8 09350946 09364747 C/K WITH L35/LF6&M30-NN8 16249458 09364720 P WITH L35&MT1&NF2 16249446 09364721 S/T WITH L35&M30&NB7 16267655 09364722 S/T WITH L35&M30&NM8 16249448 09364723 S/T WITH L35&M50&NM8 16249449 09364724 S/T WITH L35&M30&NA7 16249450 09364725 S/T WITH L35&M50&NA7 16249451 09364726 S/T WITH LF6&M30&NF2/NB6 16249452 09364727 S/T WITH L35&M50&NF2/NB6 16249453 09364728 S/T WITH L35&M30&NN8 16249465 09364729 S/T (VENEZUELA) WITH L35&M30&NN8 &W99&K53 16249554 09364730 S/T WITH L35&M50&NN8 16249466 09364731 S/T (VENEZUELA) WITH L35&M50&NN9 &W99&K53 16249555 09364732 S/T WITH L35&M30&NA3/NF2/NB6 16249556 09364733 S/T WITH LF6&M50&NF2/NB6 09350947 09364748 C/K WITH L35/LF6&M30&NN8 09350948 09364749 C/K WITH L35//LF6&M30-NN8 09350949 09364750 C/K WITH L35/LF6&M30&NN8 16249486 09360072 G VAN WITH L30&M30&NB6 16249487 09360073 G VAN WITH L30&M30&NF2 16249501 09364751 C TRUCK WITH L30&M30&NF2 16249502 09364752 C TRUCK WITH L30&M30&NB6 16249503 09364753 C TRUCK WITH L30&MG5&NF2-NN8 16249504 09364754 C TRUCK WITH L30&M30&NF2&NN8 16249505 09364755 C TRUCK WITH L30&MG5&NF2&NN8 16267292 09360074 G VAN WITH L31&M30&NF2&NM8 16249488 09360075 G VAN WITH L31&MT1&NB6 16267598 09360076 G VAN WITH L31&MT1&NF2&NM8 16249489 09360077 G VAN WITH L31&M30&NF2/NB6-NM8 16249490 09360078 G VAN WITH L31&MT1&NF2-NM8 16249491 09360079 G VAN WITH L31&MT1&NF2 16249492 09364740 G VAN WITH L31&MT1&NB6 16249493 09364741 G VAN WITH L31&M30&NA7 16249506 09364756 C/K WITH L31&M50&NA1&NF2/NB6-NM8/NN8 16249507 09364757 C/K WITH L31&M30&NA1&NC1-Y91/ZM9 16249508 09364758 C/K WITH L31&M30&NA1&NC1&Y91/ZM9 16249509 09364759 C/K WITH L31&M30&NA1&NF2/NB6- NM8/NN8/Z56/Y91/ZM9 16249510 09364760 C TRUCK WITH L31&M30&NA1&NF2/NB6&Z56 16249511 09364761 C/K WITH L31&M30&NA1&NF2/NB6&Y91/ZM9- NM8/NN8 16267310 09364808 C/K WITH L31&M50&NM8 16267311 09364809 C/K WITH L31&M30&NM8-ZM9 16259055 09364804 C/K (VENEZUELA) WITH L31&M50&NM8&W99 16259056 09364805 C/K (VENEZUELA) WITH L31&M50&NM8&W99 16249600 09364776 C/K WITH L31&M30&NM8&ZM9/ZN1-RHD 16267282 09364734 P TRUCK WITH L31&MT1&NF2&NM8 16267283 09364735 P TRUCK WITH L31&MW3&NF2&NM8 16249457 09364736 P TRUCK WITH L31&MT1&NB6&C6E/C7A/C7E 16249459 09364737 P TRUCK WITH L31&MW3&NF2-NM8 16249460 09364738 P TRUCK WITH L31&MT1&NF2-NM8 L31&MT1&C7M/C7P/CS7&NB6 16267634 09364810 C/K WITH L31&MW3&NA4&NA5&NM8 16249512 09364762 C/K WITH L31&MW3&NA4&NA5&NM8 16249513 09364763 C/K WITH L31&MW3&NA4&NA5&ZW9&NM8 16249514 09364764 C/K WITH L31&MT1&NA4&NA5&ZW9-NM8/KL6 16249515 09364765 C/K WITH L31&M50&NA1&NF2&NN8 16249516 09364766 C/K WITH L31&M30&NA1&NF2&NN8-ZM9 16249517 09364767 C/K WITH L31&M30&NA1&NF2&NN8&ZM9 16259057 09364806 C/K (VENEZUELA) WITH L31&M50&NA1&NF2 &NN8&W99 16259058 09364807 C/K (VENEZUELA) WITH L31&M30&NA1&NF2 &NN8-ZM9&W99 16259049 09364800 C/K (RHD AUSTRALIA) WITH L31&M30&NF2 &RHD (MEXICO BUILT) 16259050 09364801 C/K (RHD AUSTRALIA) WITH L31&MT1&NF2 &RHD (MEXICO BUILT) 16249518 09364768 C/K WITH L31&MT1&NA4&NA5-NM8/KL6/ZM9 16249519 09364769 C/K WITH L31&MT1&NA4&NA5&ZM9-NM8/KL6 16249447 09364739 ISUZU CALIF. NPR TRUCK WITH L31&NB6-CF7 16249461 09364780 ISUZU FED. NPR, ISUZU CALIF.NQR WITH L31-NB6 16249520 09364770 C/K WITH L31&MT1&E63&NA4&NB6-KL6& L31&MT1&NA4&NB6-KL6/ZM9 16249521 09364771 C/K WITH L31&MT1&NA4&NB6&ZM9-KL6 16249522 09364772 C/K WITH L31&MT1&NA4&NB6&ZW9-KL6 16267643 09364811 C/K WITH L31&MT1&NA4&NM8-ZM9 16267644 09364812 C/K WITH L31&MT1&NA4&NM8&ZM9 16249494 09364742 G VAN WITH L29&MT1&NB6 16249495 09364743 G VAN WITH L29&MT1&NB6 16249496 09364744 G VAN WITH L29&MT1&NF2 16249462 09364781 P TRUCK WITH L29&MT1&NF2 L29&MT1&NB6&C3D/C7R 16249523 09364773 C/K WITH L29&MT1&NB6-ZM9 L29&MT1&E62&E63&NB6 16249524 09364774 C/K WITH L29&MT1&NF2-NM8/ZM9 16249525 09364775 C/K WITH L29&MW3&NF2-NM8 16259047 09364778 C/K WITH L29&MW3&NB6&ZW9 16259048 09364779 C/K WITH L29&MT1&NB6&ZW9 16259051 09364802 C/K WITH L29&MT1&NF2&NM8 16259052 09364803 C/K WITH L29&MW3&NF2&NM8

IMPORTANT: THE CALIBRATIONS LISTED ARE FLASH CALIBRATIONS AND ARE NOT AVAILABLE FROM GMSPO. SERVICE CALIBRATIONS ARE AVAILABLE ON 1998 TECHLINE CD ROM DISC #13 AND LATER.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION DESCRIPTION LABOR TIME --------- ----------- ---------- J6355 REPROGRAMMING USE PUBLISHED LABOR OPERATION TIME

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.