P1001,P1002
Symptom: CHECK ENGINE lamp (MIL) on
EVAP canister purge valve, output from control module too low/high,
no continuity or shorting to ground/batt+
Fault symptom
CHECK ENGINE lamp (MIL) on
Condition
No continuity or shorting to ground/batt+ in the circuit to pin
5.
1.
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Begin with the ISAT command
"EVAP VALVE" in the "READ
FUNCTIONS" menu. With the engine running, the ISAT display should
show about 10%%. If it does, it is probable that no fault exists but
continue fault diagnosis as described below in any case.
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2.
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With the engine switched off, activate the ISAT command "EVAP
VALVE" in the "ACTIVATE" menu and listen to check whether the
purge valve is working (0.5 Hz).
If the valve is working, proceed to point 5. If it is
not, continue as described below.
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3.
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With the ignition in the Drive position, check that current is
present on pin 1 of the EVAP canister purge valve (from pin 87 of the
main relay).
Unplug the valve's connector and measure the resistance
across pins 1 and 2 of the valve. The correct resistance is about 26
ohms.
If the resistance is not correct, change the valve.
If the resistance is correct, check whether the valve opens by applying
current to pin 1 and connecting pin 2 to ground, using a jumper
lead.
If the valve does not open, change it.
If the valve is OK, continue with the next point.
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4.
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Warm up the engine and check whether pulses are applied to pin 2 of
the valve from pin 5 of the control module. Take a reading across pins
1 and 2 of the valve's connector.
A reading of about 0.3-0.5 V should be obtained.
Note
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The control module grounds pin 5 (pin 2 of the EVAP canister purge
valve) with 15 Hz for one minute. It then waits for one minute.
Afterwards it grounds the pin again for eight minutes - one
minute - eight minutes - and so on.
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If no pulses are present on pin 2 of the valve, check
the lead to pin 5 of the control module for continuity/
shorting.
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If pulses are present, continue as described below.
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5.
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Clear the diagnostic trouble codes, drive the car on the road to
see whether the trouble code is generated afresh. if it is, turn to
for
further diagnostic instructions.
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