Hello I have a Discovery II with 144,000 miles on it. I have replaced one of the wheel speed sensors before so I know about the 3 amigos. Replacing the sensor made them go off but now they have come back on. I hooked a OBDII up to it and got 3 codes P1884 (Engine friciton invalid, throttle position invalid, engine temp invalid, road speed invalid, engine torque invalid, engine speed invalid, engine air temp invalid, altitude shift control invalid, no reduced torque compensation) P1590(Abs rough road signal circuit malfunction hardware is ok but slabs ecu is sending an error signal) and P0102 Mass or volume air flow low input MAF signal < minimum threshold, which speed dependent. My question is could another speed sensor have gone out to throw these codes or is there a different code that is for speed sensor. Can you help me figure out what is the problem and how to go about fixing it. THanks

 

The transmission ECU, the SLABS, The BCU, and the engine ECU communicate with each other. As an example, if SLABS detects loss of throttle position signal, it disables Hill Descent Control at once unless you are already braking; and tranny won't kickdown.

The 1884 code is a generic tranny trouble code from your OBDII scanner, a more complex unit (Test book or Hawkeye) is required to get the actual code for this condition. The shop manual page attached for the tranny also lists that some of these 1884 situations turn on the M&S lights, and some don't, that may narrow the field of choices. See attached. May want to consider cleaning MAF with spray made for the purpose when vehicle is stone cold (internal part of MAF heats to 350 F + ambient, does not like thermal shock). You should also consider that some 1884 codes would represent situations where other codes would be detected by other devices monitoring the sensors. The P0102 may fall in that category. You may fix that and the rest go away.

The tranny ECU is also sensitive to weak battery, and earth (ground) wire problesm around it.

 

You can not use a general scanner to read ABS codes, need a 3 Amigos scanner or Hawkeye or spend the big bucks and have a shop read the codes for you.

 

Ok I cleaned my MAF and changed my battery. I did have a weak battery. How long do you need to drive to see if any changes occur and would my next step be to install a new MAF.