Ignition System - MIL ON/Engine Runs Rough/Low Power
Group: 01Number: 03-01
Date: Feb. 27, 2003
Subject:
Ignition Coil, Misfire Diagnosis
Model(s):
All with Eng. Code (AMB, AMU, ATC, 2001 --> 2003
ATW, AWM, AWP AVK)
Condition
^ MIL light ON/flashing
^ Engine running rough
^ Vehicle exhibits loss of power
^ Diagnostic Trouble Codes (DTCs) P0300 and any of the following DTCs - P0301, P0302, P0303, P0304, P0305 or P0306 are stored in DTC memory indicating cylinder misfire
Service
With VAS 5051/ VAS 5052 Diagnostic tool connected to the vehicle:
- Check misfire recognition.
Misfire recognition, checking:
- Switch ignition ON and start engine.
- From VAS 5051/VAS 5052 Start-up screen, select "Vehicle self diagnosis".
- Select vehicle system "01 - Engine electronics".
- Select function "02 - Interrogate fault memory".
- Check and print any stored DTC(s)
With DTC memory interrogated:
- Select "back arrow" on navigation bar.
- Select function "08 - Read data block".
For All engine codes listed
- Input "14" on keypad
- Press "Q" on keypad to confirm.
- Check for misfire recognition and print screen.
- Press the "up arrow" button to Switch to display group 015 "Checking misfire recognition of individual cylinders 1, 2, 3".
- Check misfire recognition in display fields 1 - 3 (arrows) for cylinders 1, 2, and 3.
Note:
Misfire recognition should be monitored until engine has reached operating temperature.
- Print screen.
For engine codes - AMB, ATC, AWM, AWP
- Press the "up arrow" button to Switch to display group 016 "Checking misfire recognition of the individual cylinder 4".
- Check misfire recognition in display field (arrow) for cylinder 4.
- Print screen.
- For any misfiring cylinder(s) in question, (misfire counter will be climbing if misfire is currently active).
For engine code - AVK
- Press the "up arrow" button to Switch to display group 016 "Checking misfire recognition of the individual cylinder(s) 4, 5, 6".
- Check misfire recognition in display field (arrow) for cylinder(s) 4, 5, 6.
- Print screen.
- For any misfiring cylinder(s) in question, (misfire counter will be climbing if misfire is currently active).
For All engine codes listed
If misfire counter is active for a single cylinder:
- Replace ignition coil (see note below) for that cylinder (see Ignition coil, removing).
If misfire counter is active for more than one cylinder:
- Replace ignition coil (see note below) on cylinder with most misfires, (see Ignition coil, removing).
- Recheck misfire counter again.
If misfire counter is still active for more than one cylinder:
- Contact the Dealer Technician Helpline.
Note:
If faulty coil Part No. is listed in Table shown, prior to replacement:
- Contact the Dealer Technician Helpline.
CAUTION!
Part numbers are for reference only. Always check with your Parts Dept. for the latest parts information.
Ignition coil, removing
- Removal Tool T40039 must be used for engine codes - AMB, ATC, AWM and (AWP VIN: 8N_2_00001 -->), otherwise coils may be damaged during removal.
Ignition coil, installing
- Press coil slowly into cylinder head by hand only.
^ Do not use any object to tap coil into position.
^ Do not twist coil when installing.
With ignition coil replaced:
- Check misfire again refer to "Misfire Recognition Checking".
If misfires are recognized:
- Coil may not be defective, continue to diagnose condition (refer to DTC table in Repair Manual, Group 01 - On Board Diagnostic (OBD).
If no misfires are recognized:
- Clear any stored DTCs.
- Set Readiness Code, see Readiness code, generating in Repair Manual, Group 01 - On Board Diagnostic (OBD).
Warranty information
Note:
Print outs of DTCs, Freeze frame data (if used) and measuring value blocks 014, 015, 016 must be kept on file and a copy must be included when parts are shipped to the Warranty Test Center.
When procedure applies to vehicles within the New Vehicle Limited Warranty, use the table shown.