Multi-cylinder misfire after crank position sensor job
02-04-2019, 06:34 PM
#1
Junior Member
Thread Starter
Multi-cylinder misfire after crank position sensor job
Hi, Just got my first Mercedes, a pretty black 2006 ML500
Car shut down one day and ended up being a Crank position sensor which was replaced by an independent shop.
About 50 miles later car started misfiring. Code scanner shows sometimes its cylinder 1,2,3; or 1,2,4 or sometimes 1,2,3,4,5,6,8; plus random misfire code. Once and only once in a dozen CELs, O2 sensor heater circuit was included in the list of coded as well. That has not returned.
What is the probable cause? Bad crank sensor or install? Low battery?
Doubt its all the spark plugs/coils at once.
Car drives with good power otherwise and get 20+MPG highway.
Thank You
Car shut down one day and ended up being a Crank position sensor which was replaced by an independent shop.
About 50 miles later car started misfiring. Code scanner shows sometimes its cylinder 1,2,3; or 1,2,4 or sometimes 1,2,3,4,5,6,8; plus random misfire code. Once and only once in a dozen CELs, O2 sensor heater circuit was included in the list of coded as well. That has not returned.
What is the probable cause? Bad crank sensor or install? Low battery?
Doubt its all the spark plugs/coils at once.
Car drives with good power otherwise and get 20+MPG highway.
Thank You
02-05-2019, 03:14 AM
#2
MBWorld Fanatic!
What was your original problem that you replaced the CKP Sensor? What was the code number?
If the mech. provided the sensor, he probably bought the cheapest one he could find.
If the mech. provided the sensor, he probably bought the cheapest one he could find.
02-05-2019, 10:54 AM
#3
Junior Member
Thread Starter
Would a cheap crank position sensor cause this issue?
also, car is 180k Miles
02-05-2019, 07:32 PM
#5
Junior Member
Thread Starter
No, the initial problem was that car just shut off. The current issue is random misfires on all cylinders, or 1-4, or 1,2,3,4,5,6,8. etc.
I found the shops invoice; Codes were related to CPS, pedal position malfunction and something about transmission being stuck. I guess these were due to car shutting off while driving.
CPS was replaced (by and FAE unit i just found out) and that is when misfires began.
I also just dug into and it found the bolt holding the CPS to be loose. Tightened up and will test drive now.
Are FAE sensors crappy or worth keeping?
I found the shops invoice; Codes were related to CPS, pedal position malfunction and something about transmission being stuck. I guess these were due to car shutting off while driving.
CPS was replaced (by and FAE unit i just found out) and that is when misfires began.
I also just dug into and it found the bolt holding the CPS to be loose. Tightened up and will test drive now.
Are FAE sensors crappy or worth keeping?
02-06-2019, 03:52 AM
#6
MBWorld Fanatic!
The correct part number is 003 153 28 28.
Amazon has a seller with an original M/B sensor. You must contact the seller to see if it is not a used one.
ECS Tuning is also selling an original Bosch. Also contact them if it is stamped with the Bosch logo.
https://www.amazon.com/Mercedes-Benz-Crankshaft-Position-Bosch-0032828/dp/B01F61DGT4/ref=sr_1_2?ie=UTF8&qid=1549441409&sr=8-2&keywords=0031532828
https://www.ecstuning.com/b-bosch-pa...031532828~bos/
Last edited by Maj. Dundee; 02-06-2019 at 04:23 AM.
02-22-2019, 11:44 PM
#7
Junior Member
Thread Starter
Discovered the issue was the shop left the one bolt for the crank position sensor loose. Vibration from driving and bumps would trigger it
rant: 3hr labor charge for a 20min job and they leave the only bolt loose.
rant: 3hr labor charge for a 20min job and they leave the only bolt loose.
