OK long story short.....2004 Disco 138,000 miles, I pulled out of the car wash about a block from my office (Thank God) and it went into limp mode...Check engine light was on (Mass Air Flow Circuit Low, O2 Sensor code but when this happened the Traction Control, Hill Descent light came on...I limped it to the office and hooked up the scanner to get these codes.
P0102 (stored) Mass or Volume Air Flow Sensor A Circuit Low
P0130 (stored) O2 Sensor Circuit Bank 1 Sensor 1
P1300
P0304 Cylinder 4 Misfire (stored)
P0307 Cylinder 7 Misfire (stored)
P0302 Cylinder 2 Misfire (stored)
P1663 Fuel Demand Command Signal Output Circuit (Pending)
P0300 Random/Multiple Cylinder Misfire Detected (Pending)
P0307 Cylinder 7 Misfire Detected (Pending)
P0302 Cylinder 2 Misfire Detected (Pending)

So I figured it was tune up time. Plugs/Wires(Magnacor)O2 sensors (Walker) and a Throttle Potentionmeter for good measure. All that and now she will start and idle high then smooth out and purr but as soon as I give it some gas it will stall. The Check Engine light is on along with the TC & Hill Descend and the M & S lights are flashing.
The Engine codes are:
P0103 (state: none) Mass Air Flow Sensor Fault Drive Cycle A
P0123 (state: none) Plausibility Check - Throttle Angle Drive Cycle B

It has me pretty stumped and I would appreciate any feedback or help to point me in the right direction. Thank you.

 

Most likely the MAF sensor got wet. When mine went south, after drowning, it idled...but would not accelerate.

 

X2 on MAF

 

New MAF installed and woo hoo it idles and throttles but I still have the blinking m & s lights and the hill descent/traction control light is on. I also noticed the d blinks on the shifter display and column. Whats next boys?

 

for M + S lights I would check battery terminals or it is the xyz switch I think.

 

Installed a New Optima Red Top. Fully charged and showing 14+ volt range. I had read a few things about it. I may try and change the terminal ends to see if this improves connectivity.

 

If free of corrosion you should be good there. Mine will throw the M+S from time to time but I know my negative connection won't get as tight as I'd like it to be and if I turn it off and back on it clears each time.

 

M, S, and blinking D means Limp Home Mode (3rd gear only) which can have a lot of causes but the most typical is a low battery.

 

Still have the same issues. Runs and drives fine, shifts from 1-4 gear fine yet the m&s and d lights blink. I did notice that on my live data my battery voltage was 13.4. I have pulled all battery contacts and cleaned them up and have the Optima Red Top on a charger overnight. I will reinstall battery in the morning and see what happens. I am at my wits end. lol

 

**Update** Battery and Alternator check out fine, over 14 volts under load, all terminal ends cleaned up and contact points cleaned and re-seated. Again the Disco shifts fine(gears 1-4) and seems to run great yet the M & S lights are still blinking along with the D on the digital display. The check engine light is ON as is the Traction/Hill descent. The codes are as follows:

Check Engine light is ON with code: P0122- stored- Throttle/Pedal Position Sensor/Switch A Circuit Low (I just replace the TPS sensor, perhaps the new one is faulty)
ABS code: 0202- state- none- PWM Signal Failure From Engine ECU
Transmission code: 12- state- none- CAN Message WFPDK (DKI) Invalid (FFh)

Any hints or points in the right direction for the next step would be great. Thank you all that have helped so far in this.