Aura L4-2.4L Hybrid (2009)
Fluid Pressure Sensor/Switch: All Technical Service Bulletins
A/T - MIL ON/DTC P1808/Hybrid Start/Stop Inoperative
TECHNICAL
Bulletin No.: 09-07-30-008
Date: April 02, 2009
Subject:
MIL/SES Light On or Intermittent, DTC P1808 Set, BAS Hybrid Auto Start-Stop is Inoperative (Replace PSM/TFP Switch)
Models:
2009 Chevrolet Malibu BAS Hybrid
2009 Saturn AURA BAS Hybrid, VUE BAS Hybrid
Equipped With 2.4L ECOTEC I-4 VVT Engine (VINs 5, Z - RPO LAT) and 4T45 HYDRA-MATIC(R) FWD Automatic Transmission (RPO ME7)
Condition
Some customers may comment that the BAS hybrid auto start-stop is inoperative and the MIL/SES light is on intermittently.
Technicians may find hybrid DTC P1808 (Transmission Fluid Pressure (TFP) Position Switch - Stuck Off) set.
Cause
The Pressure Switch Manifold (PSM)/Transmission Fluid Pressure (TFP) Position Switch has an additional switch input to ECM. There is a first design
and a second design switch in the 2009 model year. 2009 model year vehicles with the first design have a normally open switch. This normally open
switch may accumulate sludge and stay open which sets DTC P1808. 2009 model year vehicles with the second design have a normally closed switch
which has a longer service life.
Correction
Important
Installing a second design 2009 PSM/TFP switch into a first design BAS hybrid vehicle will cause both DTC P1808 and B1809 to set.
Note
All transmission built through 22JAN had the first design. All transmission built on or after 23JAN were second design. Refer to Transmission Tag and
Transmission Identification Information in SI.
2009 Transmission Model 9BAJ, 9BBJ or 9CKJ
These transmission models are first design and were built with the normally open PSM/TFP switch. When replacing the PSM/TFP switch on these
transmissions, use the first design switch, GM P/N 24233218.
If a complete transmission assembly is required, replace the first design transmission (9BAJ, 9BBJ, 9CKJ) with the same model transmission. Do not
install a second design transmission in a vehicle that was built with a first design transmission.
2009 Transmission Model 9CCJ, 9DAJ or 9CMJ
These transmission models are second design and were built with the normally closed PSM/TFP switch.
When replacing the PSM/TFP switch on these transmissions, use the second design switch, GM P/N 24249846.
Note
Transmission auxiliary pump priming must be performed after any service procedure is performed on the transmission that involves the draining and
refill of transmission fluid. Failure to perform the transmission auxiliary pump priming will result in damage to the auxiliary pump and possible damage
to the transmission. Use a scan tool to prime the transmission auxiliary pump.