P050A
4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P050A: Cold Start Idle Air Control System Performance
DTC P050A - Cold Start Idle Air Control System Performance
DESCRIPTION
The Electronic Throttle Control System (ETCS) controls the engine idling speed. The ETCS operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idling speed.
In addition, the ECM retards the ignition timing and the ETCS increases the intake air amount to quickly increase the catalyst temperature at cold start to reduce emissions.
MONITOR DESCRIPTION
The ECM monitors the intake air amount during idling and the ignition timing.
When the Engine Coolant Temperature (ECT) is between -10°C and 50°C (14°F and 122°F), the ECM calculates the idling intake air amount for 10 seconds, beginning 3 seconds after the engine starts.
When the accumulated value is below the threshold, the ECM interprets this as a malfunction in the Idle Speed Control (ISC) system at cold start.
The ECM also monitors the ignition timing at cold start, and judges it to be incorrect when it is advanced to the same value for a warm engine for 5 seconds or more of the 10 second monitoring period.
Example:
P050A is detected when all conditions below are met (2 trip detection logic).
1. The ECT is between -10°C and 50°C (14°F and 122°F) when the engine starts.
2. The engine idles for 13 seconds after engine start.
3. The accumulated intake air amount is below the threshold.
The ECM sets the DTC and illuminates the MIL 13 seconds after the engine is next started.
NOTE: When the negative battery terminal is disconnected during inspection or repairs, the ISC learning values are cleared. The ISC learning must be performed by warming up the engine and idling for 5 minutes with the ECT at 75°C (167°F) or more because DTCs cannot be detected with the ISC learning values cleared.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
P050A:
TYPICAL MALFUNCTION THRESHOLDS
P050A:
INSPECTION PROCEDURE
HINT: Read freeze frame data using Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Select the following the menu items: Powertrain / Engine and ECT / Trouble Code.
(e) Read the DTCs.
Result:
HINT: If any DTCs other than P050A is output, troubleshoot those DTCs first.
B -- GO TO DTC CHART
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (FUEL TRIM)
HINT: Calculate the total fuel trim values to check the characteristic deviation of the mass air flow meter.
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine and ECT / Data List / Short FT #1 and Long FT #1.
(e) Read the values displayed on the tester.
(f) Add together the Short FT #1 and Long FT #1 values to obtain the total FUEL TRIM.
OK:
Total of Short FT #1 and Long FT #1 values is between -20 % and 20 %.
OK -- CHECK THROTTLE VALVE
NG -- Continue to next step.
3. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE OCV)
(a) Connect Techstream to the DLC3.
(b) Start the engine and turn the tester on.
(c) Warm up the engine.
(d) Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1).
(e) Check the engine speed while operating the Oil Control Valve (OCV) using the tester.
OK:
NG -- CHECK AND REPAIR VVT SYSTEM
OK -- Continue to next step.
4. CHECK PCV HOSE CONNECTIONS
OK:
PCV hose is connected correctly and is not damaged.
NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.
5. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.
6. CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY
(a) Visually check that the air cleaner filter element is not excessively contaminated with dirt or oil.
OK:
Air cleaner filter element is not excessively contaminated with dirt or oil.
NG -- REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY
OK -- Continue to next step.
7. REPLACE MASS AIR FLOW METER
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
8. CHECK AND REPAIR VVT SYSTEM
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
9. REPAIR OR REPLACE PCV HOSE
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
10. REPAIR OR REPLACE AIR INDUCTION SYSTEM
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
11. REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
12. CHECK THROTTLE VALVE
(a) Check for deposits around the throttle valve and throttle valve condition.
OK:
No deposits around throttle valve and throttle valve moves smoothly.
NG -- REPAIR OR REPLACE THROTTLE BODY ASSEMBLY
OK -- Continue to next step.
13. REPLACE ECM
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
14. REPAIR OR REPLACE THROTTLE BODY ASSEMBLY
NEXT -- CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
15. CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)
NOTE: In this operation, the engine must be cold (the same level as the engine coolant temperature recorded in the freeze frame data).
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Clear the DTCs DTC Check / Clear.
(e) Switch the ECM from normal mode to check mode using the tester Check Mode Procedure.
(f) Start the engine to idle for a minute.
OK:
Stable fast idling.
(g) Read the DTCs.
OK:
No DTC output.
NEXT -- END