Actron AutoTroubleShooter CP7677 User Manual download pdf (Page 31)

31

• To test intake air tempera-

ture sensor see Temperature

Type Sensors on page 29.

EGR Valve Position

• Remove vacuum hose from

EGR valve.

• Connect hand vacuum pump

to EGR valve.

• Gradually apply vacuum to

slowly open valve. (Typi-

cally, 5 to 10 in. of vacuum

fully opens valve.)

• Depending on hook-up, the

display reading will either

increase or decrease in re-

sistance.

• The display reading should

either

start at or end at the

approximate resistance

value measured in Step 6.

9. Test Results.

Good Sensor:

Display

reading gradually increases

or decreases in resistance as

sensor is opened and closed.

Bad Sensor:

There is no

change in resistance as sen-

sor is opened or closed.

Manifold Absolute

Pressure (MAP) and

Barometric Pressure

(BARO) Sensors

This sensor sends a signal to the com-

puter indicating atmospheric pressure

and/or engine vacuum. Depending on

the type of MAP sensor, the signal may

be a dc voltage or a frequency. GM,

Chrysler, Honda and Toyota use a dc

voltage MAP sensor, while Ford uses a

frequency type. For other manufactur-

ers refer to vehicle service manual for

type of MAP sensor used.

Test Procedure (see Fig. 34):

1. Insert BLACK test lead into COM

test lead jack.

2. Insert RED test lead into

test lead jack.

3. Disconnect wiring harnc Û and

vacuum line from MAP sensor.

4. Connect jumper wire between Pin

A on wiring harness and sensor.

5. Connect another jumper wire be-

tween Pin C on wiring harness

and sensor.

6. Connect RED test lead to sensor

Pin B.

7. Connect BLACK test lead to good

vehicle ground.

8. Make sure test leads and jumper

wires are not touching each other.

9. Connect a hand held vacuum

pump to vacuum port on MAP sen-

sor.

10.Turn Ignition Key ON, but do not

start engine!

11. Turn multimeter rotary switch to...

• 20V range for DC type MAP sen-

sors.

• 4 Cylinder RPM position for Fre-

quency type MAP sensors.

Fig. 34

Ground

Red

Black

Typical

GM

MAP

Sensor

To

Computer

DC

Only

Frequency

Only

1 2 ... 26 27 28 29 30 31 32 33 34

Comments to this Manuals

No comments