SES Light and Hard Shifts

[racefan12]

The wife was driving her A4 Z28 home tonight and complained of harder shifts and half way there the SES light came on. I'm going to get it scanned in the morning. Anyone had this happen or have an idea of what it may be? Thanks for any help!

[racefan12]

fluid level is good...code was a P1870...AutoZone said something about manufactur transmission control...web site says P1870

Transmission Component Slipping/ Transmission Mechanical Transfer Case 4x4 Switch Circuit Failure

but the issue was a very hard 1-2 shift and hard shifts 2-3 and 3-4...and insult to injury, this morning the car drove flawless still had an SES...Thanks again

[Hooper]

Originally posted by racefan12
fluid level is good...code was a P1870...AutoZone said something about manufactur transmission control...web site says P1870

Transmission Component Slipping/ Transmission Mechanical Transfer Case 4x4 Switch Circuit Failure

but the issue was a very hard 1-2 shift and hard shifts 2-3 and 3-4...and insult to injury, this morning the car drove flawless still had an SES...Thanks again

I know this won't fix your hard shift issue but check your gas cap make sure it's on there tight. That can throw SES on.

[racefan12]

lol...i actually checked that first...she has left it loose before

[racefan12]

i did a search on the code 1870 and found a gm bulletin stating the following...

Harsh 1-2 Upshift, SES, MIL or CEL Illuminated, DTC P1870 Set (Replace Valve Body) #01-07-30-023A
Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)
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, 1999 (Julian Date 9015)

This bulletin is being revised to update the Parts Information. Please discard Corporate Bulletin Number 01-07-30-023 (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, 1999 (Julian Date 9015), 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).

has anyone else run into this before????

:( :( :(