Throttle Body Minimum Air Flow Check Procedure - Jeep cherokee 2000 Service Manual

14 - 42 FUEL SYSTEM
DIAGNOSIS AND TESTING (Continued)
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 19 ASD and Fuel Pump Relay Terminals—
OPERATION
• Terminal number 30 is connected to battery volt-
age. For both the ASD and fuel pump relays, termi-
nal 30 is connected to battery voltage at all times.
• The PCM grounds the coil side of the relay
through terminal number 85.
• Terminal number 86 supplies voltage to the coil
side of the relay.
• When the PCM de-energizes the ASD and fuel
pump relays, terminal number 87A connects to termi-
nal 30. This is the Off position. In the off position,
voltage is not supplied to the rest of the circuit. Ter-
minal 87A is the center terminal on the relay.
• When the PCM energizes the ASD and fuel
pump relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.
TESTING
The following procedure applies to the ASD and
fuel pump relays.
(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between termi-
nals 85 and 86. The resistance should be between 75
5 ohms.
(3) Connect the ohmmeter between terminals 30
and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.
(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
Type 2
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source. Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to the Wiring
Diagrams.
THROTTLE BODY MINIMUM AIR FLOW CHECK
PROCEDURE
The following test procedure has been developed to
check throttle body calibrations for correct idle condi-
tions. The procedure should be used to diagnose the
throttle body for conditions that may cause idle prob-
lems. This procedure should be used only after
normal diagnostic procedures have failed to
produce results that indicate a throttle body
related problem. Be sure to check for proper
operation of the idle air control motor before
performing this test.
A special fixed orifice tool (number 6714) (Fig. 20)
must be used for the following test. This tool has a
fixed internal diameter of 0.185".
Fig. 20 6714 Fixed Orifice Tool
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