P0325 code need help

[Aracobuilt]

I had a P0171 lean condition bank 1 code after having starter, timing belt, valve covers gaskets, and spark plugs replaced. Found cracked PCV hose, and replaced PCV hoses, grommet, valve, and fuel filter as preventative maintenance, and the code when away for a day. The following day the check engine light came on. I was sure it was going to be the same code but it was not. I now have a P0325 knock sensor code. I have reset it and it comes back after driving a mile. Truck idles fine with no rough idle like it did when it had P0171. I looked with a flashlight and both knock sensors seem to be connected. I will not be a happy camper if the intake needs to come off again. I am hoping they did not mess something up when the starter was replaced. Looking back I should have preformed this repair myself, but didn't due to the work involved and time. Is there anything that can be checked prior to removing the intake. I don't think the sensor are bad more like a circuit issue, but i could be wrong. I don't want to take things apart if it isn't necessary and also avoid having to order another set of intake plenum gaskets.

I had just replaced the clock spring and all that remained on my long list was to replace diff fluids and grease driveshafts.

 

[AARONTLC]

I had a P0171 lean condition bank 1 code after having starter, timing belt, valve covers gaskets, and spark plugs replaced. Found cracked PCV hose, and replaced PCV hoses, grommet, valve, and fuel filter as preventative maintenance, and the code when away for a day. The following day the check engine light came on. I was sure it was going to be the same code but it was not. I now have a P0325 knock sensor code. I have reset it and it comes back after driving a mile. Truck idles fine with no rough idle like it did when it had P0171. I looked with a flashlight and both knock sensors seem to be connected. I will not be a happy camper if the intake needs to come off again. I am hoping they did not mess something up when the starter was replaced. Looking back I should have preformed this repair myself, but didn't due to the work involved and time. Is there anything that can be checked prior to removing the intake. I don't think the sensor are bad more like a circuit issue, but i could be wrong. I don't want to take things apart if it isn't necessary and also avoid having to order another set of intake plenum gaskets.

I had just replaced the clock spring and all that remained on my long list was to replace diff fluids and grease driveshafts.

With having the starter replaced I am sure it is no coincidence. Consult the Factory Service Manual in the resources section for trouble shooting. It's probably a simple ohm test while tapping on the knock sensors with a long dowel or something. Good luck. Common for those connectors to disintegrate when removing. They probably broke the connector, and it is loose.

 

[2001LC]

Knock sensor do go bad, but not often. Most P0325, are from its wire being chewed by rodent. But I agree with @AARONTLC. It's more than likely, related to start R&R.

The knock sensor wire housing blocks, do not need to be removed. During starter R&R. But, perhaps tech did remove wire from BK1, and now is not fully plug in. Or perhaps starter was drop on sensor/wire housing block, and crack connection. Or wire housing had been removed from sensor, in a past service, wire housing lock clip broke. Now wire has come loose.

I'll assume 98-05 4.7L. Which we can see under intake with flashlight.
I'd use a borescope, to look close at sensor and wire housing. If wire housing looks not fully plug in. I try making tool, to press in, in situ.

If no issue found with borescope under IM at sensor or its wires. I'd run through FSM P0325 DTC Diagnostics.

If P0171 comes back.
I'd monitor fuel trims, see how each bank doing.
I'd look close at IM gasket and IM bolts. I've seen a few issues after IM removed:

• Gasket not replace with new.
• Gasket not installed white tabs up.
• IM bolts not torqued down.
• Debris or shop towel, not removed from intake port.

 

[Aracobuilt]

Thanks for the detailed replies.

Where is the connector on the other end of the knock sensor wiring harness? I might try that first, since it seems like the least difficult thing to check.

 

[Aracobuilt]

I have recently noticed a slight rough idle sometimes. Odd thing is I don't have P0171 anymore, only P0325. Will a knock sensor circuit issue cause a rough idle. I can't seem to find any vacuum leaks coming from any hoses since replacing the PCV hoses, valve, and grommet and i checked the torque on the intake manifold bolts and they appear to be fine.