P050A

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P050A: Cold Start Idle Air Control System Performance

DTC P050A - Cold Start Idle Air Control System Performance

DESCRIPTION





This monitor will run when the engine is started with the engine coolant temperature at -10 to 50°C (14 to 122°F). The DTC will be set after the engine idles for 13 seconds (2 trip detection logic).
The DTC is designed to monitor the idle air control at cold start. When the engine is started with the engine coolant temperature at lower than 50°C (122°F), the ECM (PCM) measures the accumulated mass air flow at engine idling. If it does not reach the criteria within 10 seconds, the ECM (PCM) interprets this as a malfunction. The MIL is illuminated and a DTC is set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).
The ETCS (Electronic Throttle Control System) controls the idle speed. The ETCS operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.
NOTE:
When the negative battery terminal is disconnected during inspections or repairs, the ISC (Idle Speed Control) learning values are cleared. This DTC cannot be set with the ISC learning values cleared.

The ISC learning is performed when the engine is warmed up and has been idling for 5 minutes.





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE

PROCEDURE

1. CHECK DTCS
Result:
Any other DTCs are not set.
NG -- GO TO DIAGNOSTIC TROUBLE CODE CHART
OK -- Continue to next step.
2. READ SHORT-TERM AND LONG-TERM FUEL TRIMS
HINT: The total of the short-term fuel trim (Short FT) and long-term fuel trim (Long FT) is used to discover a problem in the induction system (between air cleaner and intake manifold).
(a) Allow the engine to idle.
(b) Enter the following menus: Powertrain / Engine and ECT / Data List.
(c) Read the value of Short FT #1 and Long FT #1 (bank 1).
(d) Read the value of Short FT #2 and Long FT #2 (bank 2).
Result:
Total of Short FT and Long FT is between -20% and 20%
NG -- CHECK VVT SYSTEM
OK -- Continue to next step.
3. CHECK THROTTLE BODY
(a) Check for deposits around the throttle valve and throttle valve condition.
Result:
No deposits around throttle valve and throttle valve moves smoothly.
OK -- REPLACE ECM
NG -- REPAIR OR REPLACE THROTTLE BODY
4. CHECK VVT SYSTEM
(a) Allow the engine to idle with the engine warmed up.
(b) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1) or Control the VVT System (Bank 2).
(c) Turn on Control the VVT System (Bank 1) (or Control the VVT System (Bank 2)) to advance the valve timing.
(d) Check the engine condition.
Result:
The engine stalls or idles roughly when Control the VVT System is ON. (VVT system is OK)
NG -- CHECK AND REPAIR VVT SYSTEM
OK -- Continue to next step.
5. CHECK PCV SYSTEM
(a) Allow the engine to idle.
(b) Pinch the positive crankcase ventilation (PCV) hose.
(c) Check the engine rpm.
Result:
The engine rpm rises when the PCV hose is pinched.
NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.
6. CHECK AIR CLEANER FILTER
(a) Visually check that the air cleaner filter is not excessively contaminated with dirt or oil.
NG -- REPLACE AIR CLEANER FILTER
OK -- Continue to next step.
7. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leakage.
OK -- REPLACE MASS AIR FLOW METER
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
8. REPAIR OR REPLACE THROTTLE BODY
NEXT -- CHECK DTCS
9. REPLACE ECM
NEXT -- CHECK DTCS
10. CHECK AND REPAIR VVT SYSTEM
NEXT -- CHECK DTCS
11. REPAIR OR REPLACE PCV HOSE
NEXT -- CHECK DTCS
12. REPLACE AIR CLEANER FILTER
NEXT -- CHECK DTCS
13. REPAIR OR REPLACE AIR INDUCTION SYSTEM
NEXT -- CHECK DTCS
14. REPLACE MASS AIR FLOW METER
NEXT -- CHECK DTCS
15. CHECK DTCS
(a) Check that the engine coolant temperature is -10 to 50°C (14 to 122°F).
(b) Clear the DTC.
(c) Enter the check mode using the Techstream.
(d) Allow the engine to idle for 1 minute.
(e) Check that no DTC is present.
NEXT -- END