Thanks in advance. Any advice is welcome
Look here for some possibilities:
Tell your mechanic to get a real analyzer and start looking at the waveform coming off the sensor rather than just thrashing around replacing things without doing any real diagnosis.
If you watch the actual signals you may find that the poor signal coming off the sensor which produces the P0335 is a _symptom_ of the engine running rough rather than the cause.
On the other hand, you may see ignition noise is getting into the sensor wiring due to a bad ground. Without actually seeing the signal coming off the sensor you won't know.
I'd definitely check all related ground points and make sure the block ground cable is clean and tight of course.
--scott
Check TSB 02-06-04-059
Document ID: 1212710 #02-06-04-059: Engine Runs Rough, Service Engine Soon Light On, DTC P0300 or P0335 Set (Shim Crankshaft Sensor) - (Dec
16, 2002)Subject:Engine Runs Rough, Service Engine Soon Light On, DTC's P0300 or P0335 Set (Shim Crankshaft Sensor) Models:2002-03 Chevrolet Astro, Blazer, Express, Silverado and S-10 Truck Models
2002-03 GMC Jimmy, Safari, Savana, Sierra and Sonoma Truck Models with 4.3L V-6 Engine (VINs W, X - RPOs L35, LU3)Condition Some owners may comment on a rough running condition or a Service Engine Soon (SES) light being illuminated. Upon investigation, the technician may find a DTC code P0300 or P0335.
Cause The crankshaft sensor may be contacting the reluctor wheel.
Correction Remove the crankshaft sensor. Refer to the Crankshaft Position Sensor Replacement procedure in the Engine Controls-4.3L sub-section of the Service Manual. After removing the sensor, inspect the end of it for witness marks that would indicate contact with the crankshaft. If contact with the reluctor ring is indicated, then inspect the front cover for cracking or other signs of alignment concerns. If the inspection indicates that the cover is causing mis-alignments, replace the cover. If replacing the cover, then the 0.5mm shim is not needed.
If the inspection of the front cover indicates that the cover is not the cause of mis-alignments, then the sensor should be shimmed. Add one shim between the sensor and the front cover. If the concern still exists, then add the second shim. Unless the sensor has been rubbed through the casing or deformed by contact with the crankshaft, it should not be replaced.
In either case, the crankshaft relearn procedure should be performed after any repairs.
Parts Information
Part Number: 12565102 Description: Shim, 0.5mm thick Qty: 1-2
Sensor Crankshaft Position: as req'd
12562910
indeed.
good post.
to the o.p., when you have a tech that "replaces stuff", especially the engine computer which is /highly/ unlikely to experience a fault like this, you need to take your business to someone that actually knows what they're doing. failure to look up tsb's, failure to understand why a sensor code would return after sensor replacement, both are fundamental problems that are costing you money.
to other techs - this is the problem with "black box" learning. replacing the box only gets you so far. understanding what the box does gets you much further. if you know how the sensor works, and how its output relies on its interaction with its input, you can fix the problem first time. and in this case, without having to replace anything.
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