00-06-04-037A
Automatic Transmission - Harsh Shifts/MIL ON/DTC's P0716/P0717 Set
November, 2001


Subject:  Service Engine Soon (SES) Light On with DTCS P0716 and/or P0717 Set (Repair Input Speed Sensor Wiring at Transaxle Wiring Pass-thru Connector)

Models:  2000-2002 Buick Century, LeSabre, Park Avenue, Regal, 2002 Buick Rendezvous, 2000-2002 Chevrolet Cavalier, Impala, Malibu, Monte Carlo, Venture, 2000-2001 Chevrolet Lumina, 2000-2002 Oldsmobile Alero, Aurora, Intrigue, Silhouette, 2000-2002 Pontiac Bonneville, Grand Am, Grand Prix, Montana, Sunfire, 2001-2002 Pontiac Aztek


This bulletin is being revised to add additional models and revise text.  Please discard Corporate Bulletin Number 00-06-04-037 (Section 06-Engine/Propulsion System).


Condition

Some customers may comment that the Service Engine Soon (SES) indicator is illuminated and that while the light is illuminated, transmission shifts are extremely harsh.


Cause

This condition may be caused by an intermittent connection of the Input Speed Sensor (ISS) (circuits 1230 and/or 1231) at the transaxle 20-way connector to the wiring harness interface.


Correction

The ISS is a magnet with a wire hooked to each end (the north pole and south pole of the magnet).  The magnet is mounted extremely close to the transaxle's input drive sprocket.  The passing teeth of the drive sprocket cause the magnet of the ISS to generate a low alternating (AC) voltage signal.  This is defined as a Permanent Magnet (PM) generator.  This low (AC) voltage signal is transmitted to the Powertrain Control Module (PCM) by circuits 1230 and 1231.  The PCM converts the AC signal to a digital signal (On/Off) which can be displayed by the Tech 2 as RPM.

When the vehicle is being driven and the PCM detects a large change in the ISS AC signal (1300 RPM) in an extremely short period of time, (less than 0.8 second), a DTC P0716 is set and the PCM commands maximum line pressure (i.e. firm shifts).

When the vehicle is being driven and the vehicle speed is greater than 8 km/h (5 mph) and the ISS AC signal to the PCM is at a low or zero value, DTC P0717 is set and the PCM commands maximum line pressure (i.e. firm shifts).

Replacement of the ISS within the transaxle is not required.  Parts returned have all been found to be within engineering specifications.

Step	Action	Yes	No
1	Did you perform the Powertrain Diagnostic System Check?	Go to Step 2	Go to Powertrain Diagnostic System Check
2	Connect the Tech 2 scan tool to the ALDL connector on the vehicle. Turn ON the ignition with the engine OFF. Important:  Before clearing the DTC, record the DTC Freeze Frame and Failure Records as displayed on the Tech 2. Use he Clear Info function to erase the Freeze Frame and Failure Records from the PCM. Clear the DTC. Start the engine.  Leave the transmission in Park. Select Transmission ISS on the Tech 2. Is the transmission input speed (Transmission ISS) at or near the value displayed for engine RPM?	Go to Step 3	Go to Step 3
3	With the engine running and the transaxle in par, wiggle the vehicle wiring harness at the transmission pass through connector by hand.  If unable to access the connector, puch the vehicle rearward against the parking pawl of the transmission and let it bounce forward.  Repeat this motion several times while observing the ISS value on the Tech 2. Did the Transmission ISS (RMP) value change?	Go to Diagnostic Aids	Go to Diagnostic Aids

Diagnostic Aids

DTC P0716/P0717 Input speed Sensor Circuit - Intermittent/Open

If a DTC was recorded and the Freeze Frame and Failure Records back it up, a problem existed at one time with the wiring and/or the connectors between the transaxle and the PCM.  Therefore, a thorough inspection and/or repair to the wiring harness at the transaxle 20-way connector for one or more of the following conditions may be warranted.

• The wiring harness is stretched too tightly or other components are pressing on the connector body itself causing a downward pressure on the connector body and possible intermittent contact of the wiring terminals.  Ensure proper clearance to any other components and wiring (i.e. hoses, battery cables, etc.).
• The terminals are not fully seated into the cavity of the connector body.
• The male terminals in the transaxle portion of the connector may be in the wrong position (i.e. bent).
• The female terminals may be loose and are not making proper contact.  Check the tension with the proper terminal tester from the GM Terminal Test Kit J 35616-A or J 3561-92.  If tension is low, replace the terminal.  Do not try to re-form the terminal.
• The crimp of the terminal to the wire may not be satisfactory (i.e. loose, over insulation, etc.).
• The wiring connector is not properly seated and locked in position.  Ensure proper seating of the connector into the transaxle and that the connector is properly locked in place.

Warranty Information

Labor Operation	Description	Labor Time
N6630	Wiring and/or Connector (Transaxle) - Repair	0.5 hr

For vehicles repaired under warranty, use the table as shown.