DTC Troubleshooting

P050A, P50B DIAGNOSIS PROCEDURE

Step	Action	YES	NO
1	Was "Engine Basic Inspection" performed?	Go to Step 2.	Go to ENGINE BASIC INSPECTION:J24B .
2	Was "Engine and Emission Control System Check" performed?	Go to Step 3.	Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK:J24B .
3	DTC check Is there DTC(s) other than P050A and P050B?	Go to applicable DTC (s).	Go to Step 4.
4	Air intake system check Check air intake system for clogging and air inhabit. Is it in good condition?	Go to Step 5.	Repair or replace defective parts.
5	PCV system check Check PCV system parts or system. PCV valve: PCV VALVE INSPECTION PCV hose: PCV HOSE INSPECTION Are they in good condition?	Go to Step 6.	Repair or replace defective parts.
6	Exhaust system check Check exhaust system, see EXHAUST SYSTEM CHECK . Is it in good condition?	Go to Step 7.	Repair or replace defective parts.
7	Throttle body assembly check Check throttle body assembly. Throttle actuator: THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION TP sensor: THROTTLE BODY ASSEMBLY ON-VEHICLE INSPECTION Are they in good condition?	Go to Step 8.	Replace throttle body assembly.
8	ECT sensor circuit and performance check Check ECT sensor for circuit and performance referring to Step 3 and 4 of DTC P0116/P0125/P0128 . Is it in good condition?	Go to Step 9.	Repair or replace defective parts of wire harness.
9	Ignition system check Check ignition system parts or system. Ignition system:, see IGNITION SYSTEM CHECK . Ignition spark: IGNITION SPARK TEST Ignition timing: IGNITION TIMING INSPECTION Are they in good condition?	Go to Step 10.	Repair or replace defective parts.
10	EVAP system check Check EVAP system parts or system, see EVAP CANISTER PURGE SYSTEM INSPECTION . Are they in good condition?	Go to Step 11.	Repair or replace defective parts.
11	Engine mechanical system check Check engine mechanical parts or system. Engine compression: COMPRESSION CHECK Engine vacuum: ENGINE VACUUM CHECK Valve clearance: IMRC (INTAKE MANIFOLD RUNNER CONTROL) SYSTEM DESCRIPTION Valve timing: CAMSHAFT AND TAPPET REMOVAL AND INSTALLATION Are they in good condition?	Substitute a known-good ECM and recheck.	Repair or replace defective parts.