- Mass Air Flow (MAF) meter
- Air induction system
- PCV hose connections
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000PF4036X |
| Title: 3UR-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
DTC |
P0101 |
Mass Air Flow Circuit Range / Performance Problem |
DESCRIPTION
Refer to DTC P0102
.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0101 |
Conditions (a), (b), (c), (d) and (e) continue for more than 10 seconds (2 trip detection logic): (a) Engine running (b) Engine coolant temperature 70°C (158°F) or higher (c) Throttle Position (TP) sensor voltage 0.24 V or more and 3.6 V or less (d) Average engine load value ratio less than 0.85, or more than 1.17 (varies with estimated engine load) Average engine load value ratio = Average engine load based on MAF meter output / Average engine load estimated from driving conditions (e) Average air-fuel ratio less than -15%, or more than 15% |
|
MONITOR DESCRIPTION
The MAF meter is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and to provide an appropriate air-fuel ratio. Inside the MAF meter, there is a heated platinum wire which is exposed to the flow of intake air. By applying a specific electrical current to the wire, the ECM heats it to a specific temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to the wire and internal thermistor. The voltage level is proportional to the airflow through the sensor, and the ECM uses it to calculate the intake air volume.
The ECM monitors the average engine load value ratio to check the MAF meter for malfunctions. The average engine load value ratio is obtained by comparing the average engine load calculated from the MAF meter output to the average engine load estimated from the driving conditions, such as the engine speed and the throttle opening angle. If the average engine load value ratio is below the threshold value, the ECM determines that the intake air volume is low, and if the average engine load value ratio is above the threshold value, the ECM determines that the intake air volume is high.
If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is stored.
MONITOR STRATEGY
|
Related DTCs |
P0101: Mass air flow meter rationality |
|
Required Sensors/Components (Main) |
Mass air flow meter |
|
Required Sensors/Components (Related) |
Crankshaft Position (CKP) sensor, Engine Coolant Temperature (ECT) sensor and Throttle Position (TP) sensor |
|
Frequency of Operation |
Continuous |
|
Duration |
10 seconds |
|
MIL Operation |
2 driving cycles |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Monitor runs whenever following DTCs not present |
P0115 - P0118 (ECT sensor) P0120 - P0223, P2135 (TP sensor) P0125 (Insufficient ECT for Closed Loop) P0335 (CKP sensor) |
|
Throttle position (TP sensor voltage) |
0.2 V or more and 3.6 V or less |
|
Time after engine start |
5 seconds or more |
|
Battery voltage |
10.5 V or more |
|
Engine coolant temperature |
70°C (158°F) or more |
|
Estimated load |
30 to 100% |
|
IAT sensor circuit |
OK |
|
ECT sensor circuit |
OK |
|
CKP sensor circuit |
OK |
|
TP sensor circuit |
OK |
|
Canister pressure sensor circuit |
OK |
|
EVAP leak detection pump |
OK |
|
EVAP vent valve |
OK |
TYPICAL MALFUNCTION THRESHOLDS
|
Both of following conditions 1 and 2 met |
- |
|
1. Averaged engine load value ratio |
Less than 0.85, or more than 1.15 (varies with estimated engine load) |
|
2. Averaged air-fuel ratio |
Less than -15%, or more than 15% |
WIRING DIAGRAM
Refer to DTC P0102
.
CONFIRMATION DRIVING PATTERN
HINT:
Performing this confirmation pattern will activate the mass air flow performance monitor.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Turn the Techstream on.
-
Clear DTCs
.
- Start the engine, and warm it up until the engine coolant temperature reaches 70°C (158°F) or higher.
- Drive the vehicle at approximately 100 km/h (62 mph) for 20 seconds or more.
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
- Check if any DTCs (any pending DTCs) are output.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
|
1. |
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0101) |
(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 DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
P0101 is output |
A |
|
P0101 and other DTCs are output |
B |
HINT:
If any DTCs other than P0101 are output, troubleshoot those DTCs first.
|
|
2. |
CHECK AIR INDUCTION SYSTEM |
(a) Check the air induction system for vacuum leak
.
OK:
No leak from air induction system.
|
|
3. |
CHECK PCV HOSE CONNECTIONS |
(a) Check the PCV hose connections.
OK:
PCV hose is connected correctly and is not damaged.
|
|
|