Chrysler 300M 2002 Service Manual page 2549

DRIVEABILITY - NGC
P0300-MULTIPLE CYLINDER MISFIRE —
TEST
3 Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
CYLINDER LEAKAGE TEST - must be within specifications
CAM LOBES - must not be worn excessively
WEAK or BROKEN VALVE SPRINGS
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL INJECTOR - plugged or restricted injector; control wire not connected to
correct injector
Are there any engine mechanical problems?
Yes → Repair as necessary.
→ Go To 4
No
4 With the DRBIII , read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
DTC.
In the FREEZE FRAME, are the adaptive fuel percentages greater than +/- 15%?
Yes → Refer to the Driveablitiy Category and perform the Checking Fuel
→ Go To 5
No
5 With the DRBIII , read the FREEZE FRAME DATA.
Use the FREEZE FRAME DATA and attempt to determine the cause of the Misfire
DTC.
In the FREEZE FRAME DATA, is the engine RPM over 3000 and the operating temp
normal?
Yes → Test CMP and CKP signals with Lab Scope, check valve timing,
→ Go To 6
No
6 Note: Anything that affects the speed of the crankshaft can cause a misfire
DTC.
The following are other possible causes for mis-fire:
Injector harness connectors, PCM power grounds, restricted exhaust, intake restric-
tion, damaged trigger wheel, contaminated fuel, carbon build up on valves, or the
accessory drive belt (serpentine belt).
Check for any TSB's that may relate to a Misfire DTC.
Do any of the above causes exist?
Yes → Repair as necessary.
→ Go To 7
No
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Delivery symptom.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
and perform running vacuum test.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Continued
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APPLICABILITY
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