PCM - Engine Sags, Hesitates, Surge/Occasional Shudder
NO: 18-18-94GROUP: Vehicle Performance
DATE: Sep. 9, 1994
SUBJECT:
Sags, Hesitation, Surge, and/or Occasional Shudder
MODELS:
1995 (PL) Neon
NOTE:
THIS BULLETIN APPLIES TO VEHICLES BUILT PRIOR TO AUG. 5, 1994 (MDH 08-05-XX).
SYMPTOM/CONDITION:
Sags, hesitation, surge and/or occasional engine shudder. The symptoms listed, depending on vehicle operation, may occur at different road speeds (highway/city traffic), throttle position (vehicle speeding up/slowing down), or may be encountered when various accessories or loads are applied.
DISCUSSION:
The diagnosis and repair procedures should be followed on all vehicles with the listed symptom/condition. However, this repair procedure will not affect normally occurring changes in engine power that occur on vehicles with air conditioning.
When A/C is selected, the compressor cycles to prevent evaporator freeze-up. This cycling occurs after vehicle cool down - in milder ambients at lower blower speeds, or at higher engine/vehicle speeds. These cycles can be as short as 5 seconds.
Even if A/C is not selected, the compressor will operate and can cycle when the air direction control is placed at or between the defrost and floor/defrost symbols.
During acceleration from a stop or slow speed, depending on throttle position, the compressor may turn off for a period of time to enhance engine performance. The compressor also turns off for a period of time during wide open throttle.
It is normal to feel some change in engine power when the compressor cycles. This normal compressor cycling will not be affected by this repair procedure.
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRBIII) with the appropriate diagnostic procedure manual, verify that all engine systems are functioning as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order for future reference, and repair as necessary. If no codes are present and all systems are functioning correctly, proceed with the repair.
PARTS REQUIRED:
REPAIR PROCEDURE:
This bulletin involves replacing the Powertrain Control Module (PCM), and on manual transaxle equipped vehicles built prior to January 28, 1994, replacing the Crankshaft Position Sensor.
1. Remove the PCM as outlined on Page 8D - 1 in the 1995 Neon Service Manual Supplement (Publication No. 81-270-5025A), and replace it with the appropriate unit called out in "PARTS REQUIRED".
2. Perform the Relearn - Cam/Crank Alignment Procedure. Using the DRB III, select Engine, select Misc., then select Option # 5 - Relearn - Cam/Crank.
NOTE:
THE FOLLOWING STEP APPLIES TO VEHICLES EQUIPPED WITH A MANUAL TRANSAXLE AND BUILT PRIOR TO JAN. 28, 1994 (MDH 01-28-XX).
3. Remove Crankshaft Position Sensor, outlined on page 8D - 13 in the 1995 Neon Service Manual (Publication No. 81-270-5025). Replace it with P/N 5235377.
4. Type the required information on the Authorized Modification Label (as illustrated), and attach near the VECI Label.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No: Powertrain Control Module (MTX/ATX)
08-19-01-95 0.4 Hrs.
Crank Position Sensor (MTX)
08-15-80-91 0.2 Hrs.
FAILURE CODE: AM - Authorized Modification