How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask SUPRYZE Your Own Question
SUPRYZE, Technician/Shop Foreman
Category: Car
Satisfied Customers: 2158
Experience:  GM & Saab Certified, ASE Master Technician
Type Your Car Question Here...
SUPRYZE is online now
A new question is answered every 9 seconds

99 callaway Range Rover has Diagnostic Trouble transmission

Resolved Question:

My '99 Callaway Range Rover has Diagnostic Trouble Code: P01178 (T) AMFR correction at its masximum positive value... Would you translate this for me?
What does AMFR mean. I think I need to change my Mass AirFlow Sensor. Could a bad MAFS affect my transmission? It is shifting hard from 3rd to Drive. All else is OK. Thanks for any help here! Paul
Submitted: 7 years ago.
Category: Car
Expert:  SUPRYZE replied 7 years ago.

Hello! AMFR stands for Air Mass Flow Rate. Basically, the code indicates that the computer is having to add/subrtract fuel as compared to what the Mass Air Flow meter says is coming in. This could be caused by vacuum leaks (from the intake gaskets or vacuum lines) or a faulty Mass Air Flow meter.

When we get problems like this in, we hook a smoke machine up to the intake, to help pinpoint vacuum leaks (if any). If you have a suitable scantool to monitor live data, you can spray around the intake manifold and vacuum lines/intake duct work with carb cleaner and watch for changes in the data. Sudden spikes in the adaptation values or O2 sensors indicate a leak.


If all that checks out OK, then you may have a faulty MAF sensor. The MAF sensor is also used as a load input, to help with transmission shifting, so a faulty MAF sensor could cause transmission issues, but without actually looking at the vehicle, these are only "possible" causes.



SUPRYZE and other Car Specialists are ready to help you