Envoy 2WD V6-4.3L VIN W (1998)
Torque Converter Clutch Solenoid: All Technical Service Bulletins
A/T - 4L60-E Harsh 1-2 Gear Upshift/MIL/SES/CEL ON
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 01-07-30-023B
Date: March, 2002
TECHNICAL
Subject:
Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set
(Replace Valve Body)
Models:
1996 Buick Roadmaster
1996 Cadillac Fleetwood
1999-2000 Cadillac Escalade
1996-2000 Chevrolet Camaro, Corvette
1996-2000 Pontiac Firebird
1996-2000 Chevrolet and GMC Light Duty Truck Models
1996-2000 Oldsmobile Bravada
with 4L60-E Automatic Transmission (RPO M30)
Built Prior to January 15, 2000 (Julian Date 0015)
This bulletin is being revised to update VIN Breakpoint Date information and revise the Parts Information table. Please discard Corporate Bulletin
Number 01-07-30-023A (Section 07 - Transmission/Transaxle).
Condition
Some customers may comment on a harsh 1-2 upshift and the Check Engine Light or Service Engine Soon indicator is illuminated.
Diagnosis
Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.
The scan tool may show a DTC P1870 set as a history code.
A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°
C (200°F).
Cause
The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results
in poor, or no, TCC apply.
Important:
^
DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive
cycle) before setting a P1870 history code.
^
When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
^
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two
consecutive trips (Ignition cycles, with a drive cycle).
^
When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
^
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp
(MIL).
Correction
Install a control valve body with the revised TCC regulator and isolator valves. Refer to the Parts Information table below. These valves are used in all
transmissions produced after January 15, 2000 (Julian Date 0015), and all of the service parts currently available through GMSPO contain revised TCC
