Toyota Sequoia (2005). Manual - part 76

A21226

Wire Harness Side:

Mass Air Flow Meter Connector

M1

E2G

VG

B17412

E8

ECM Connector

E2G

VG

–

DIAGNOSTICS

ENGINE

DI–107

301

4

Check for open and short in harness and connector between mass air flow meter
and ECM.

PREPARATION:
(a)

Disconnect the M1 mass air flow meter connector.

(b)

Disconnect the E8 ECM connector.

CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:

Standard:

Tester Connection

Specified Condition

VG (M1–3) – VG (E8–30)

Below 1 

Ω

E2G (M1–2) – E2G (E8–29)

Below 1 

Ω

VG (M1–3) or VG (E8–30) – 

Body ground

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Replace mass air flow meter.

A21375

Engine Room J/B:

EFI 
No. 2 Fuse

A21226

Wire Harness Side:

Mass Air Flow Meter Connector

M1

+B

A21376

Engine Room J/B:

EFI Relay

DI–108

–

DIAGNOSTICS

ENGINE

302

5

Check for open and short in harness and connector between mass air flow meter
and EFI relay.

PREPARATION:
Remove the EFI No. 2 fuse from the engine room J/B.
CHECK:
Check the resistance in the EFI No. 2 fuse.
OK:

Standard:
Below 1 

Ω

PREPARATION:
(a)

Install the EFI No. 2 fuse.

(b)

Disconnect the M1 mass air flow meter connector.

(c)

Remove the EFI relay from the engine room J/B.

CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:

Standard:

Tester Connection

Specified Condition

+B (M1–1) – Engine Room J/B (EFI

relay terminal 1)

Below 1 

Ω

+B (M1–1) or Engine room J/B (EFI relay

terminal 1) – Body ground

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Check ECM power source circuit
(See page 

DI–493

).

B17412

E2G

E8 ECM Connector

A21226

Wire Harness Side:

Mass Air Flow Meter Connector

M1

VG

E2G

B17412

E8

ECM Connector

E2G

VG

–

DIAGNOSTICS

ENGINE

DI–109

303

6

Check continuity between terminal E2G of ECM connector and body ground.

CHECK:
Check the resistance between terminal of the E8 ECM connec-
tor and body ground.
OK:

Standard:

Tester Connection

Specified Condition

E2G (E8–29) – Body ground

Below 1 

Ω

NG

Replace ECM (See page 

SF–80

).

OK

7

Check for open in harness and connector between mass air flow meter and ECM.

PREPARATION:
(a)

Disconnect the M1 mass air flow meter connector.

(b)

Disconnect the E8 ECM connector.

CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:

Standard:

Tester Connection

Specified Condition

VG (M1–3) – VG (E8–30)

Below 1 

Ω

E2G (M1–2) – E2G (E8–29)

Below 1 

Ω

VG (M1–3) or VG (E8–30) – 

Body ground

10 k

Ω

 or higher

E2G (M1–2) or E2G (E8–29) – 

Body ground

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Replace mass air flow meter.

DI–110

–

DIAGNOSTICS

ENGINE

304

DTC

P0101

Mass or Volume Air Flow Circuit Range/
Performance Problem

CIRCUIT DESCRIPTION

Refer to DTC P0100, P0102 and P0103 on page 

DI–102

.

DTC No.

DTC Detecting Condition

Trouble Area

P0101

After engine is warmed up, conditions (a), (b), (c) and (d) con-

tinue for more than 10 seconds: 

(2 trip detection logic)

(a) Throttle valve fully closed

(b) Voltage output of the mass air flow meter is more than 2.2

V.

(c) Engine coolant temperature is more than 70 

°

C (158 

°

F).

(d) Engine speed is less than 2,000 rpm.

Mass air flow meter

Conditions (a), (b) and (c) continue for more than 10 seconds

at engine speed: (2 trip detection logic)

(a) Engine speed is more than 300 rpm.

(b) Voltage output of the mass air flow meter is less than 1.0 V.

MONITOR DESCRIPTION

The MAF (Mass Air Flow) meter helps the ECM calculate the amount of air flowing through the throttle valve.
The ECM uses this information to determine the fuel injection time and provide a proper air fuel ratio. Inside
the MAF meter, there is a heated platinum wire exposed to the flow of intake air. By applying a specific current
to the wire, the ECM heats this wire to a given temperature. The flow of incoming air cools the wire and an
internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the volt-
age applied to these components in the MAF meter. The voltage level is proportional to the air flow through
the MAF meter. The ECM interprets this voltage as the intake air amount. If there is a defect in the MAF meter
or an open or short circuit, the voltage level will deviate outside the normal operating range. The ECM inter-
prets this deviation as a defect in the MAF meter and sets a DTC.
Example: 
If the voltage is more than 2.2 V at idle or less than 1.0 V at idle OFF, the ECM interprets this as a defect
in the MAF meter and sets a DTC.

MONITOR STRATEGY

R l t d DTC

P0101

Mass air flow meter rationality (Low voltage)

Related DTCs

P0101

Mass air flow meter rationality (High voltage)

Main sensors/components

Mass air flow meter

Required sensors/components

Related sensors/components

Engine speed sensor, Engine coolant tempera-

ture sensor, Throttle position sensor

Frequency of operation

Continuous

Duration

10 sec.

MIL operation

2 driving cycles

Sequence of operation

None

DI3HM–13