Dodge ZB 2005 Service Manual page 1213

DRIVEABILITY - GAS
P0300-MULTIPLE CYLINDER MIS-FIRE —
TEST
2 NOTE: Anything that affects the speed of the crankshaft can cause a misfire
DTC.
NOTE: When a Misfire is detected for a particular cylinder, the PCM will
shut down that cylinders Injector Control circuit.
- Visually inspect the engine for any of the following conditions.
- Worn serpentine belt
- Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump.
- Misalignment Water pump, P/S Pump and A/C Compressor pulleys
- Corroded PCM power and ground circuits.
- Improper CKP, CMP, MAP, and TP Sensor mounting
- Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector,
Ign coil, etc.
- Vacuum leaks
- Restricted Air Induction system or Exhaust system.
Were any of the above conditions present?
Yes → Repair as necessary.
→ Go To 3
No
3 Turn the ignition off.
Disconnect the Ignition Coil harness connectors.
Disconnect the Fuel Injector harness connectors.
Ignition on, engine not running.
With the DRBIII , actuate the ASD Relay.
Using a 12-volt test light connected to ground, probe the (K342) ASD Relay Output
circuit at the Ignition Coil harness connector and Fuel Injector harness connector.
Does the test light illuminate brightly?
Yes → Go To 4
→ Repair the excessive resistance or short to ground in the (K342)
No
4 Turn the ignition off.
Disconnect the Ignition wire from the spark plug.
Disconnect the Fuel Injector harness connector of the cylinder being tested.
NOTE: Before continuing inspect the ignition wire for damage or carbon
tracking. Replace as necessary.
Install a spark tester on the ignition wire.
While cranking the engine observe the spark coming from the spark tester.
NOTE: A crisp blue spark that is able to jump the gap of the spark tester
should be generated.
Is good spark present?
Yes → Go To 5
→ Go To 14
No
ACTION
Perform POWERTRAIN VERIFICATION TEST VER - 5.
ASD Relay Output circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Continued
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APPLICABILITY
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