For 1990-2009 cars

# Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)

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 regulator and isolator valves.

Important: If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.

• | Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).

• | The torque converter is not blue or overheated.

• | The transmission fluid is not burned or has no burned odor.

• | The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).

### Parts Information

Model Year | Vehicle Platform | Engine (RPO) | Transmission (RPO) | Transmission Broadcast Code | P/N
--- | --- | --- | --- | --- | ---
1996 | S Truck | 2.2L (LN2) | 4L60-E (M30) | SAD | 24217855
1996 | C Truck (Mexico) | 5.7L (LO5) | 4L60-E (M30) | CPD | 24217856
1996 | C/K Truck G Van | 5.0L (L30) | 4L60-E (M30) | CCD, CFD, KBD, WAD, WBD | 24217856
1996 | C/K Truck G Van | 5.7L (L31) | 4L60-E (M30) | CHD, CJD, KCD, CMD, CUD, KPD, YDD, FFD, WCD, WHD | 24217857
1996 | F Car Y Car | 5.7L (LT1) | 4L60-E (M30) | FFD, YDD | 24217857
1996 | D Car | 5.7L (L31) | 4L60-E (M30) | AHD | 24217857
1996 | S/T Truck M/L Van | 4.3L (L35) | 4L60-E (M30) | TBD,TAD, MSD, MDD | 24217860
1996 | C/K Truck G Van | 4.3L (L35) | 4L60-E (M30) | CAD, CBD, KAD | 24217861
1996 | S/T Truck | 4.3L (LF6) | 4L60-E (M30) | SHD, TLD | 24217862
1996 | B Car | 4.3L (L99) | 4L60-E (M30) | BBD, BCD | 24217863
1996 | B Car (Includes Police Pkg.) | 5.7L (LT1) | 4L60-E (M30) | BFD, BWD, BKD | 24217864
1996 | F Car | 3.8L (L36) | 4L60-E (M30) | FCD, FBD | 24217865
1997 | S Truck | 2.2L (LN2) | 4L60-E (M30) | SAD | 24217866
1997 | C/K Truck G Van | 4.3L (L35) | 4L60-E (M30) | CAD, CBD, KAD | 24217867
1997 | S/T Truck M/L Van | 4.3L (L35) 4.3L (LF6) | 4L60-E (M30) | SHD, TLD, TBD, TAD, MSD, MDD | 24217868
1997 | C Truck (Mexico) | 5.7L (L31) | 4L60-E (M30) | CPD | 24217869
1997 | C/K Truck G Van | 5.0L (L30) | 4L60-E (M30) | CCD, CFD, KBD | 24217869
1997 | C/K Truck G Van | 5.7L (L31) | 4L60-E (M30) | CJD, CHD, KCD | 24217870
1997 | F Car Y Car | 5.7L (LS1) | 4L60-E (M30) | FFD, YDD | 24217870
1997 | F Car | 3.8L (L36) | 4L60-E (M30) | CFD, FBD | 24217871
1998 | C/K Truck G Van | 5.7L (L31) 5.0L (L30) | 4L60-E (M30) | ADD, AFD, AJD, ALD, AWD, CCD, CFD, KBD, CHD, CJD, KCD | 24221155
1998-2000 | C/K Truck G Van S/T Truck M/L Van | 4.3L (L35) 4.3L (LF6) | 4L60-E (M30) | TAD, MSD, CAD, CBD, KAD, WBD, SHD | 24221154
1998-2000 | S Truck | 2.2L (LN2) 2.2L (L43) | 4L60-E (M30) | SAD | 24221153
1998-2000 | F Car | 3.8L (L36) | 4L60-E (M30) | FBD, FCD | 24221159
1998-2000 | F Car Y Car | 5.7L (LS1) | 4L60-E (M30) | FFD, YDD | 24221158
1998-2000 | C/K Truck (Includes Police Pkg.) G Van | 5.7L (L31) 5.0L (L30) | 4L60-E (M30) | LHD, LSD, LUD, LPD, KXD, CPD | 24221161
1999-2000 | C/K Truck | 4.8L (LR4) | 4L60-E (M30) | CCD, CFD, KBD | 24221162
1999-2000 | C/K Truck | 5.3L (LM7) | 4L60-E (M30) | CJD, CHD, KCD | 24221162

Parts are currently available from GMSPO.

### Warranty Information

For vehicles repaired under warranty, use:

Labor Operation | Description | Labor Time
--- | --- | ---
K6560 | Valve Body - R&R or Replace | Use Published Labor Operation Time