P0385 and P0345 codes on a hot day. Need advice.
#1
06-17-2017, 12:50 PM
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P0385 and P0345 codes on a hot day. Need advice.
Hey Guys:
2004 F150 FX4 5.4l engine with 213000 km on it.
Driving on the highway pulling a boat on a hot day with the A/C blasting. Slowed down in a speed zone and the engine started running rough and the engine light came on. Code P0385 (Crankshaft position sensor) was noted. After a few minutes it started running normally again. I cleared the code that night and reseated the connector to the crankshaft sensor. Next day the same thing happened except this time it threw code P0345 (Camshaft position sensor). Again after a few minutes it returned to running normally. Went the remainder of the trip without the A/C on and there were no further occurances of code or rough running symtoms. Took it to a mechanic and they cannot recreate a situation that would throw a code of any sort.
They indicated that it might be a timing chain issue where the heat condition makes it stretch sufficiently to alter the angles that those two sensors are observing. No sure that makes sense to me as I have never heard of this. Chain failure maybe but stretching to cause a sensor condition???? Not sure I buy that. Do you wise fellows have any better thoughts?
Thanks in advance.
2004 F150 FX4 5.4l engine with 213000 km on it.
Driving on the highway pulling a boat on a hot day with the A/C blasting. Slowed down in a speed zone and the engine started running rough and the engine light came on. Code P0385 (Crankshaft position sensor) was noted. After a few minutes it started running normally again. I cleared the code that night and reseated the connector to the crankshaft sensor. Next day the same thing happened except this time it threw code P0345 (Camshaft position sensor). Again after a few minutes it returned to running normally. Went the remainder of the trip without the A/C on and there were no further occurances of code or rough running symtoms. Took it to a mechanic and they cannot recreate a situation that would throw a code of any sort.
They indicated that it might be a timing chain issue where the heat condition makes it stretch sufficiently to alter the angles that those two sensors are observing. No sure that makes sense to me as I have never heard of this. Chain failure maybe but stretching to cause a sensor condition???? Not sure I buy that. Do you wise fellows have any better thoughts?
Thanks in advance.
#2
06-22-2017, 08:09 PM
Senior Member
Well, the 'hot' day having something to do with it seems a 'stretch' (no pun intended) since engine operating temperature is generally regulated by a thermostat to around 195 degrees.
But do not discount the chain stretch theory as relates to your codes. The chains are long (with 122 links). A few thousandths ware in each link can cumulatively add up to quiet a bit. Then if a guide breaks it aggravates the situation. Code 0345 is threshold driven in the PCM software. The Cam Position Sensors are not "Interrupt driven" in the PCM software. Instead, the PCM 'polls' the CPS sensors looking for the presence of one of the Phaser 'fingers' that should appear in front of the hall effect sensor at just the right time - with respect to the Crankshaft Position Sensor. IF phaser finger is not there within a prescribed 'window' of time - it triggers a P0345. This frequently occurs during startup - leading to mechanics suspecting Battery or Starter issues. But in fact, it is likely to occur during startup due to tensioners relaxed and chain slack being at maximum. This code WILL occur (and be HARD - reoccurring every time) if the chain jumps a link - (in the right direction). The other code --- which I suspect is just around the corner is P0022, where that cam cannot return to FULL ADVANCE position (ie: over-retarded).
But do not discount the chain stretch theory as relates to your codes. The chains are long (with 122 links). A few thousandths ware in each link can cumulatively add up to quiet a bit. Then if a guide breaks it aggravates the situation. Code 0345 is threshold driven in the PCM software. The Cam Position Sensors are not "Interrupt driven" in the PCM software. Instead, the PCM 'polls' the CPS sensors looking for the presence of one of the Phaser 'fingers' that should appear in front of the hall effect sensor at just the right time - with respect to the Crankshaft Position Sensor. IF phaser finger is not there within a prescribed 'window' of time - it triggers a P0345. This frequently occurs during startup - leading to mechanics suspecting Battery or Starter issues. But in fact, it is likely to occur during startup due to tensioners relaxed and chain slack being at maximum. This code WILL occur (and be HARD - reoccurring every time) if the chain jumps a link - (in the right direction). The other code --- which I suspect is just around the corner is P0022, where that cam cannot return to FULL ADVANCE position (ie: over-retarded).