I'll start with a little background...
About a month ago a customer brought their 2012 LR4 (under warranty) to the dealership for a check engine light. I checked the fault codes and find P0172 and P0175, which means both banks are running rich. I've personally never seen this an any 5.0L trucks, or 4.4L, so I thought this was a bit unusual. I started doing some basic checks and found the vehicle was fitted with K&N air filters. I noticed oil sitting on top of the filters and determined that the oil on the filter had likely contaminated the mass air flow sensors. I replaced both sensors and air filters, test drove the vehicle, and everything seemed okay.
Fast forward to last week...
Our dealership gets a letter from K&N stating that there was a "complete misdiagnosis" and that there is nothing wrong with the mass air flow sensors. They included photos of the thermistor in the MAFS under a microscope and performed a bench test (whatever that means). They reimbursed the customer for the cost of the repairs I performed, and now are demanding that we reimburse them for my misdiagnosis. They also claim that this misinformation has caused substantial damage to their reputation.
According to K&N, I should have started by replacing both air filters to see if the fault followed. They included some info from Alldata which includes possible causes which includes...
-Leaking fuel injectors
-Fuel return line restricted
-Fuel rail pressure sensor bias
-EVAP purge valve is leaking when the canister is full
-Engine oil is contaminated
-Damaged or contaminated mass air flow sensor
Note that nowhere on that list does it say anything about an air filter.
The letter also says, "That is why CRC makes and sells Mass Air Flow Sensor cleaner as they do need to be cleaned periodically even with an O.E. paper air filter." I know for a fact that no where in any Land Rover service literature does it mention anything about cleaning a mass air flow sensor. Also, that is very poor logic since CRC also makes throttle body cleaner, which Land Rover specifically recommends against.
According to the Land Rover Warranty Policies and Procedures Manual, any damage to the vehicle caused by the fitment of non factory components are excluded from the new vehicle warranty.
They do not state whether or not the testing of the sensors was performed before or after cleaning, but they do claim that they were clean to start with. I'd also like to note that we did not agree to this testing, and that this level of testing to determine whether or not the sensors were at fault would be on the customer at the normal shop rate which would be cost prohibitive.
I'd also like to note that my manager called the customer to confirm that the vehicle is fixed and the fault has not returned. The customer is 100% satisfied and believes that my diagnosis was correct.
I'm just curious, what are everyone's thoughts? Keep in mind, I am paid by the job, not by the hour, so any significant diagnostic time would be charged to the customer. If I remember correctly I charged for the standard initial 1.0 hr of diag and an additional .2 hrs - .5 hrs for the air filters and sensors.
About a month ago a customer brought their 2012 LR4 (under warranty) to the dealership for a check engine light. I checked the fault codes and find P0172 and P0175, which means both banks are running rich. I've personally never seen this an any 5.0L trucks, or 4.4L, so I thought this was a bit unusual. I started doing some basic checks and found the vehicle was fitted with K&N air filters. I noticed oil sitting on top of the filters and determined that the oil on the filter had likely contaminated the mass air flow sensors. I replaced both sensors and air filters, test drove the vehicle, and everything seemed okay.
Fast forward to last week...
Our dealership gets a letter from K&N stating that there was a "complete misdiagnosis" and that there is nothing wrong with the mass air flow sensors. They included photos of the thermistor in the MAFS under a microscope and performed a bench test (whatever that means). They reimbursed the customer for the cost of the repairs I performed, and now are demanding that we reimburse them for my misdiagnosis. They also claim that this misinformation has caused substantial damage to their reputation.
According to K&N, I should have started by replacing both air filters to see if the fault followed. They included some info from Alldata which includes possible causes which includes...
-Leaking fuel injectors
-Fuel return line restricted
-Fuel rail pressure sensor bias
-EVAP purge valve is leaking when the canister is full
-Engine oil is contaminated
-Damaged or contaminated mass air flow sensor
Note that nowhere on that list does it say anything about an air filter.
The letter also says, "That is why CRC makes and sells Mass Air Flow Sensor cleaner as they do need to be cleaned periodically even with an O.E. paper air filter." I know for a fact that no where in any Land Rover service literature does it mention anything about cleaning a mass air flow sensor. Also, that is very poor logic since CRC also makes throttle body cleaner, which Land Rover specifically recommends against.
According to the Land Rover Warranty Policies and Procedures Manual, any damage to the vehicle caused by the fitment of non factory components are excluded from the new vehicle warranty.
They do not state whether or not the testing of the sensors was performed before or after cleaning, but they do claim that they were clean to start with. I'd also like to note that we did not agree to this testing, and that this level of testing to determine whether or not the sensors were at fault would be on the customer at the normal shop rate which would be cost prohibitive.
I'd also like to note that my manager called the customer to confirm that the vehicle is fixed and the fault has not returned. The customer is 100% satisfied and believes that my diagnosis was correct.
I'm just curious, what are everyone's thoughts? Keep in mind, I am paid by the job, not by the hour, so any significant diagnostic time would be charged to the customer. If I remember correctly I charged for the standard initial 1.0 hr of diag and an additional .2 hrs - .5 hrs for the air filters and sensors.
