Terminal and Connector Inspection
Check for Wiring Harness
1.

Check for damaged harness and terminals including rubber seals :

(1)

contact resistance, oxidation, corrosion, bent or broken terminals

(2)

harness connector connection, loose wires etc.

2.

Check for poor connection between ECM and component :

backed out terminal, improper mating, broken locks and poor terminal to wire connection

3.

ARE THE WIRES O.K ? & ARE THE CONNECTIONS O.K ?

YES

a.

Go to "Signal Circuit Inspection" procedure

NO

a.

Repair as necessary and go to " Verification of Vehicle Repair " procedure

Signal Circuit Inspection
Problem Verification
1.

DTCs listed below are stored in the scan tool

P0100/C001_C002_C003

2.

Check items with the scan tool and the multimeter

(1)

Wiring harness inspection

(2)

Sensor supply voltage from ECM

(3)

Waveform from MAFS

3.

Specification

1)

Resitance : below 1 Ω for open in the wire

2)

Resitance : infinite for short to ground in the wire

3)

Voltage : below 0.5V for short to power in the wire

4)

Sensor supply voltage : Approx. 5V

note

Refer to the component and full circuit for connector configrations details

C001 : Air Flow Sensor Circuit - Low Input
4.

Disconnect the MAFS and then turn the ignition switch ON.

Measure the voltage between the MAFS terminal 4 and the MAFS terminal 3

5.

IS THERE A BATTERY VOLTAGE ?

YES

a.

Go to step 3

NO

a.

Repair open or short in the wire between the MAFS terminal 4 and the fuse No.21 (10A)

b.

Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.

c.

Replace the fuse if the fuse is broken.

d.

Repair as necessary for wiring harness or connector terminal

e.

Go to step 3

6.

Measure the voltage for the MAFS terminal 2 and terminal 3

7.

IS THERE approx. 5 V ?

YES

a.

Go to step 7

NO

a.

Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.

b.

Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.

c.

Repair as necessary for wiring harness or connector terminal

d.

Go to step 5

8.

Measure the voltage at the ECM terminal 16/C230-2 after turning the ignition switch ON directly.

9.

IS THERE approx. 5V ?

YES

a.

Recheck open or short in the wire between MAFS terminal 2 and the ECM terminal 16/C230-2.

b.

Go to step 7

NO

a.

Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM

b.

Go to step 7

10.

Check the signal waveform at the MAFS termianl 1 and the APS terminal 2 when depressing the accelerator pedal fully one time.

WAVEFORM ANALYSIS

This test should be inspected after depressing the HOLD mode from run during the sudden acceleration. As accel pedal with the MAFS is pressed down fully, the intensity of the waveform increases from less than 1V to over 4V. The waveform pattern become increasing upward rapidly when the engine speed increases. If the waveform pattern becomes distorted after the sudden acceleration, replace the MAFS

8. IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?

YES

a.

Go to "Verification of Vehicle Repair" procedure.

NO

a.

Replace the MAFS

C002 : Air Flow Sensor Circuit - High Input
11.

Disconnect the MAFS and then turn the ignition switch ON.

Measure the voltage between the MAFS terminal 4 and the MAFS terminal 3

12.

IS THERE A BATTERY VOLTAGE ?

YES

a.

Go to step 7

NO

a.

Repair open or short in the wire between the MAFS terminal 4 and the fuse No.21 (10A)

b.

Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.

c.

Inspect the fuse No.21 (10 A) in the dash fuse box and replace the fuse if the fuse is broken.

d.

Repair as necessary for wiring harness or connector terminal

e.

Go to step 3

13.

Measure the voltage between the MAFS terminal 2 and the MAFS terminal 3

14.

IS THERE approx. 5 V ?

YES

a.

Go to step 7

NO

a.

Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.

b.

Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.

c.

Repair as necessary for wiring harness or connector terminal

d.

Go to step 5

15.

Measure the voltage at the ECM termial 16/C230-2 after turning the ignition switch ON directly.

16.

IS THERE approx. 5V ?

YES

a.

Recheck open or short in the wire between MAFS terminal 2 and the ECM terminal 16/C230-2.

b.

Go to step 7

NO

a.

Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM

b.

Go to step 7

17.

Check the signal waveform at the MAFS terminal 1 and the APS terminal 2 when depressing the accelerator pedal fully one time.

WAVEFORM ANALY

This test should be inspected after depressing the HOLD mode from run during the sudden acceleration.As accel pedal with the MAFS is pressed down fully, the intensity of the waveform increases from less than 1V to over 4V. The waveform pattern become increasing upward rapidly when the engine speed increases. If the waveform pattern becomes distorted after the sudden acceleration, replace the MAFS

8. IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?

YES

a.

Go to "Verification of Vehicle Repair" procedure.

NO

a.

Replace the MAFS

C003 : Air Flow Sensor Circuit - General Error
note

In this DTC P0100/C003 case, P1526(Sensor supply voltage 1 malfunction) and P0120 (APS 1) may be detected together.

18.

Disconnect the MAFS and then turn the ignition switch ON.

Measure the voltage between the MAFS terminal 2 and the MAFS terminal 3 after disconnection with the ignition switch ON

19.

IS THERE approx. 5 V ?

YES

a.

Intermittent failure, system is O.K at this time.

b.

Check for poor connections or losse wire at the MAFS and the ECM.

c.

Go to "Verification of Vehicle Repair" procedure.

NO

a.

Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.

b.

Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2

c.

Repair as necessary for wiring harness or connector terminal

d.

Go to step 3

20.

Measure the voltage at the ECM terminal 16/C230-2 after turning the ignition switch ON directly.

21.

IS THERE approx. 5V ?

YES

a.

Recheck open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2. Go to "Verification of Vehicle Repair" procedure.

NO

a.

Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM

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