Line Pressure Check Procedure Tools Required Important: Before performing a line pressure check, verify that the pressure control (PC) solenoid valve is receiving the correct electrical signal from the PCM. Caution: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result it the vehicle moves unexpectedly. J 21867Universal Pressure Gauge Set 1. Install a Scan Tool. 2. Start the engine and set the parking brake. 3. Check for a stored Diagnostic Trouble Code (DTC). 4. Repair the vehicle, if necessary. 5. Check the fluid level. Refer to the Transmission Fluid Checking Procedure. 6. Check the manual linkage for proper adjustment. 7. Turn the engine OFF. Remove the oil pressure test hole plug and install the J 21867. 8. Put the gear selector in PARK range and set the parking brake. 9. Start the engine and allow the engine to warm up at idle Notice: Total test running time should not be longer than two minutes, or else transmission damage could occur. Notice: Refer to Fastener Notice in Cautions and Notices. Parts Information 10. Access the PC solenoid valve control test on the Scan Tool. Zoom Sized for Print 11. Increase the PC solenoid as shown actual current from 0.0 to 1.0 amps in 0.1 amp increments. Allow the pressure to stabilize for five seconds after each pressure change. Read the corresponding line pressure on the J 21867. 12. Refer to the Line Pressure specification table. Compare the data to the table. 13. If pressure readings differ greatly from the table, refer to Incorrect Line Pressure. 14. Remove the J 21867. 15. Apply sealant, P/N 12345382 (in Canada, P/N 10953489), to the oil pressure test hole plug. 16. Install the oil pressure test hole plug. Tighten Tighten the oil pressure test hole plug to 12 N.m (106 lb in).
1. Look at the BARO PID. Refer to the Barometric Pressure Reference Chart in this article. At sea level, BARO should read about 159 Hz (29.91 in. Hg). As a reference, Denver, Colorado at 1524 meters (5000 ft.) altitude should be about 144 Hz (24.88 in.Hg). Normal learned BARO variability is up to +/- 6 Hz (+/- 2 in. Hg.). If BARO indicates a higher altitude than you are not at (7 or more Hz lower than expected), you may have MAF contamination. If available, Service Bay Diagnostic System (SBDS) has a Manifold Absolute Pressure (MAP) sensor that can be used as a barometric pressure reference. Use “MAP/BARO” test under “Powertrain,” “Testers and Meters.” Ignore the hookup screen. Connect GP2 to the reference MAP on the following screen. 2. On a fully warmed up engine, look at Long Term Fuel Trim at idle, in Neutral, A/C off, (LONGFT1 and/or LONGFT2 PIDs). If it is more negative than -12%, the fuel system has learned lean corrections which may be due to the MAF sensor over-estimating air flow at idle. Note that both Banks 1 and 2 will exhibit negative corrections for 2-bank system. If only one bank of a 2-bank system has negative corrections, the MAF sensor is probably not contaminated. 3. On a fully warmed up engine, look at MAF voltage at idle, in Neutral, A/C off (MAF V PID). If it’s 30% greater than the nominal MAF V voltage listed in the Powertrain Control/Emissions Diagnosis (PC/ED) Diagnostic Value Reference Charts for your vehicle, or greater than 1.1 volts as a rough guide, the MAF sensor is over-estimating air flow at idle. 4. If at least tow of the previous three steps are true, proceed to disconnect the MAF sensor connector. This puts the vehicle into Failure Mode and Effects Management (FMEM). In FMEM mode, air flow is inferred by using rpm and throttle position instead of reading the MAF sensor. (In addition, the BARO value is reset to a base/unlearned value.) If the lean driveability symptoms go away, the MAF sensor is probably contaminated and should be replaced. If the lean driveability symptoms do not go away, go to the PC/ED Service Manual for the appropriate diagnostics.