QuestionI have a 2000 Pontiac Grand prix with 114,000 miles. for the past 8 months or so i have been having problems with jerking and stalling when the car goes from frist to second or second to thrid gear. I have finally taken it to a GM dealer and the above three codes were given. I have been advised to replace the Mass Air Flow Sensore and told that the clutches in the transmission are going bad and that the transmission should be replaced. I researched this same issue on Edmunds.com forum pages and found that other pontiac owners had the same experience and had eventually (after thousands of dollars worth of repairs) replaced the Power Control Module and that cleared up the problem. Before I begin sinking money into this car I am looking for any other tips, advice, suggestions.... thanks.
AnswerHi
With the p0101 I would suspect the MAF.
Witht he other 2 codes, just my experience and advice would be the Transmission PCS (Pressure Control Solonoid).
This solonoid is VERY common fault, and created the codes you have stored, AND symptons you describe.
It is a fairly costly repair, the transmission side cover needs to be removed ALOT of labor, but the part is not that expensive, per say.
I personally do not see the PCM at fault. That is JUST my thought.
I have seen more problems like yours with the faulty PCS other than the PCM.
Now This is JUST advice.
You CAN take it to other shops and get their advice. I know it usually costs but it would sure beat the transmission overhaul price.
Also Take it to a Tranny shop, maybe and get their advice.
Bring them this post and have them preform a Line pressure test while observing the PSC on a scan tool.
Here is procedure
Line Pressure Check Procedure along with the Line Pressure Specification Table below, to determine if actual versus desired pressures are within the values specified. The Scan Tool is only able to control the PC solenoid valve in PARK and NEUTRAL with the vehicle stopped. This protects the clutches from extremely high or low pressures in DRIVE or REVERSE ranges.
Refer to the Line Pressure Specification Table below. The pressures in the table assume a temperature of 70°C. The pressure will vary with a change in temperature.
Line Pressure Specification Table Pressure Control Solenoid Valve Current
Approximate Line Pressure*
Metric
English
0 amp
1675-2137 kPa
243-310 psi
0.1 amp
1662-2124 kPa
241-308 psi
0.2 amp
1613-2103 kPa
234-305 psi
0.3 amp
1551-2068 kPa
225-300 psi
0.4 amp
1448-1986 kPa
210-288 psi
0.5 amp
1310-1903 kPa
190-276 psi
0.6 amp
1172-1751 kPa
170-254 psi
0.7 amp
1000-1531 kPa
145-222 psi
0.8 amp
793-1227 kPa
115-178 psi
0.9 amp
565-896 kPa
82-130 psi
1 amp
469-641 kPa
68-93 psi
1.1 amp
448-552 kPa
65-80 psi
*Approximate Line Pressure is measured at an engine speed of 1400 RPM.
If the actual versus desired pressures are not within the values specified, clean the valve body and replace the PC solenoid valve, if necessary.
Check the PC solenoid valve actual versus desired pressures to verify the new PC solenoid valve is responding correctly.
Line Pressure Check Procedure
Important: Before performing a line pressure check, verify that the pressure control (PC) solenoid valve is receiving the correct electrical signal from the PCM.
Install a Scan Tool.
Caution: Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.
Start the engine and set the parking brake.
Check for a stored Diagnostic Trouble Code (DTC).
Repair the vehicle, if necessary.
Check the fluid level.
Check the manual linkage for proper adjustment.
Turn the engine OFF. Remove the oil pressure test hole plug and install trans fluidd pressure gage.
Put the gear selector in PARK range and set the parking brake.
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.
Access the PC solenoid valve control test on the Scan Tool.
Increase the PC solenoid 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 trans fluidd pressure gage.
Refer to the Line Pressure specification table. Compare the data to the table.
If pressure readings differ greatly from the table, refer to Incorrect Line Pressure.
Remove the trans fluidd pressure gage.
Apply sealant, P/N 12345382 (in Canada, P/N 10953489), to the oil pressure test hole plug.
Install the oil pressure test hole plug.
This is JUST advice from experience and Publishe data.
I will not be held responsible if any of this is wrong.
I hope this helps.
Good Luck
Pawl
