- Throttle body assembly
- Mass air flow meter
- PCV system
- Air cleaner filter element
- Air induction system
- VVT system
- ECM
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000002TZB00SX |
| Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
DTC |
P050B |
Cold Start Ignition Timing Performance |
DESCRIPTION
This monitor will run when the engine is started at an engine coolant temperature of -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 ignition timing at cold start. When the engine is started at an engine coolant temperature of lower than 50°C (122°F), the ECM checks the ignition timing at engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 tip detection logic).
NOTICE:
When the negative battery terminal is disconnected during inspections or repairs, the ISC (Idle Speed Control) learning values are cleared. This DTC cannot be stored with the ISC learning values cleared.
HINT:
The ISC learning is performed when the engine is warmed up and has been idling for 5 minutes.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P050B |
Insufficient ignition timing retard at cold start (2-trip detection logic) |
|
MONITOR STRATEGY
|
Related DTCs |
P050B: Cold start ignition timing performance |
|
Required Sensors / Components (Main) |
Throttle body assembly |
|
Required Sensors / Components (Related) |
Mass air flow meter Engine Coolant Temperature (ECT) sensor |
|
Frequency of Operation |
Once per driving cycle |
|
Duration |
10 seconds |
|
MIL Operation |
2 driving cycles |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Battery voltage |
8 V or more |
|
Time after engine start |
3 seconds or more |
|
Starter |
OFF |
|
ECT at engine start |
-10°C (14°F) or more |
|
ECT |
-10 to 50°C (14 to 122°F) |
|
Engine idling time |
3 seconds or more |
|
Fuel-cut |
OFF |
|
Vehicle speed |
Less than 3 km/h (1.875 mph) |
|
Atmospheric pressure |
76 kPa (570 mmHg) or more |
TYPICAL MALFUNCTION THRESHOLDS
|
Accumulated time when ignition timing retard value is cut off |
5 seconds or more |
INSPECTION PROCEDURE
HINT:
-
DTC P050B may be set when the engine has the symptoms listed below. If necessary, check the trouble areas listed below.
Symptom
Factor
Trouble Area
Low idle speed when engine is cold (immediately after engine start)
Excessive engine friction
- Engine oil deterioration
- Drive belt tension
- A/C compressor
- Generator
- Vane pump
Rough idle when engine is cold (immediately after engine start)
Abnormal combustion
Fuel quality
- Read freeze frame data using the 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.
PROCEDURE
|
1. |
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050B) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
P050B is output |
A |
|
P050B and other DTCs are output |
B |
HINT:
If any DTCs other than P050B are output, troubleshoot those DTCs first.
|
|
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 the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2.
(e) Read the values displayed on the Techstream.
(f) Add together the Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2 values to obtain the total fuel trim.
OK:
Total of Short FT #1 and Long FT #1, or Short FT #2 and Long FT #2 values is between -20% and 20%.
|
|
3. |
INSPECT THROTTLE BODY |
(a) Check that there are no deposits around the throttle valve.
OK:
No deposits around the throttle valve.
|
|
4. |
REPLACE ECM |
(a) Replace the ECM
.
|
5. |
PERFORM ACTIVE TEST USING TECHSTREAM (OCV OPERATION) |
(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream on.
(d) Warm up the engine.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT System (Bank 1) or Control the VVT System (Bank 2).
(f) Check the engine speed while operating the Oil Control Valve (OCV) using the Techstream.
OK:
|
Tester Operation |
Specified Condition |
|---|---|
|
OCV OFF |
Normal engine speed |
|
OCV ON |
Soon after OCV switched from OFF to ON, engine idles roughly or stalls |
|
|
6. |
CHECK PCV SYSTEM |
(a) Start the engine.
(b) Pinch the positive crankcase PCV hose.
(c) Check the engine rpm.
OK:
The engine rpm rises when the PCV hose is pinched.
|
|
7. |
INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY |
(a) Visually check that the air cleaner filter element is not excessively contaminated with dirt or oil.
OK:
The air cleaner filter element is not excessively contaminated with dirt or oil.
|
|
8. |
CHECK AIR INDUCTION SYSTEM |
(a) Check the air induction system for vacuum leaks
.
OK:
No leak from the air induction system.
|
|
9. |
REPLACE MASS AIR FLOW METER |
(a) Replace the mass air flow meter
.
|
10. |
REPAIR OR REPLACE THROTTLE BODY |
(a) Repair or replace the throttle body
.
|
11. |
CHECK AND REPAIR VVT SYSTEM |
|
12. |
REPAIR OR REPLACE PCV SYSTEM |
|
13. |
REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY |
|
14. |
REPAIR OR REPLACE AIR INDUCTION SYSTEM |
|
|
15. |
CHECK WHETHER DTC OUTPUT RECURS (DTC P050B) |
NOTICE:
For this operation, the engine must be cold (the same level as the engine coolant temperature recorded in the freeze frame data).
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the DTCs
.
(e) Switch the ECM from normal mode to check mode using the Techstream
.
(f) Start the engine and idle it for one minute.
(g) Check that the idling is stable and fast.
OK:
Stable fast idle
(h) Read the DTCs.
OK:
No DTC is output.
|
|
|