Evap Purge Solenoid testing?

Is there a way to test this? On my '01 XJ I've been getting 2 CEL codes recently. P0442 & P0455... Small and Large Evap leak detected.

I've checked all the evap lines visually and noticed no leaks. I did notice some dry-rot on the rubber connections, but nothing cracked or obvious. I will replace those connections as preventative soon. One thing I did notice is that my Evap Purge Solenoid is not making any noise like it's always done. No clicking or ticking... and when I unplugged/replugged there was no change. Should there be some voltage I can check at the plug?

Just wondering if there's a way to check it? I'm assuming it's quit working... but just want to make sure it's not a fuse or something that could've blown before throwing parts at this.

Thanks

Redsnake said:

Is there a way to test this? On my '01 XJ I've been getting 2 CEL codes recently. P0442 & P0455... Small and Large Evap leak detected.

I've checked all the evap lines visually and noticed no leaks. I did notice some dry-rot on the rubber connections, but nothing cracked or obvious. I will replace those connections as preventative soon. One thing I did notice is that my Evap Purge Solenoid is not making any noise like it's always done. No clicking or ticking... and when I unplugged/replugged there was no change. Should there be some voltage I can check at the plug?

Just wondering if there's a way to check it? I'm assuming it's quit working... but just want to make sure it's not a fuse or something that could've blown before throwing parts at this.

Thanks

Click to expand...

You can use a power probe or voltmeter to check the circuit.

Unplug the electrical connector from the solenoid.

The White wire receives a constant 12 volts from fuse 10 in the Junction Block with the ignition switch is to PUN and the Pink/Black tracer wire is the control wire from the PCM. The PCM privides a ground to the solenoid 5 to 10 times per second.

Start the engine and let it come up to operating temp. The engine needs to be in closed loop for the solenoid to operate and to do this test.

Using a voltmeter (20 VDC scale), touch the White wire pin cavity with the (+) probe and the (-) probe to a clean engine ground or the battery negative post. You should see battery voltage.

Touch the Pink/Black tracer wire pin cavity with the meter (-) probe and the meter (+) probe to the battery postive post. You should see your voltmeter needle cycle every 5 to 10 seconds.

Check the line from the fuel pump to the evaporator canister under the jeep.

Mine totally rusted out and threw the "big evaporator leak" code.

Sidewinder CC said:

You can use a power probe or voltmeter to check the circuit.

Unplug the electrical connector from the solenoid.

The White wire receives a constant 12 volts from fuse 10 in the Junction Block with the ignition switch is to RUN and the Pink/Black tracer wire is the control wire from the PCM. The PCM privides a ground to the solenoid 5 to 10 times per second.

Start the engine and let it come up to operating temp. The engine needs to be in closed loop for the solenoid to operate and to do this test.

Using a voltmeter (20 VDC scale), touch the White wire pin cavity with the (+) probe and the (-) probe to a clean engine ground or the battery negative post. You should see battery voltage.

Touch the Pink/Black tracer wire pin cavity with the meter (-) probe and the meter (+) probe to the battery postive post. You should see your voltmeter needle cycle 5 to 10 per second.

Click to expand...

Corrections (in blue) to the prevcious post.

Thx guys! The temps were in the upper 60's here yesterday and today in the mid-teens... hopefully the weather warms a bit and I'll get back out there and run these tests and checks.

You could cap the pump at its output to prove the pump is working. I can hear it running as it makes a tap-tap-tap sound on the firewall. Can also feel it by touching the housing.

Recently the wife's '01 threw a code and it was just the little green screw-on cap was loose.

This several years after finding cracks in the single-wall rubber connector hose sections (2!) between pump and canister. Connectors replaced with double-wall fuel line of teh right size.