TDCI 2.2 Technical help need Fault PO100

Landrover TDCI 2.2 2012

3 weeks ago the engine management light came on, limp mode, diagnostic came up with fault PO100 - Mass or Volume Air Flow Sensor A Circuit.

Fitted new Air Flow Meter, checked all pipes, rerouted the plug to the air flow meter, noticed a couple had their insulated cracked so tidied up wiring. Vehicle run find for 3 weeks.

Then tonight after driving for 4 miles, battery warning light flickered, engine stuttered, engine management light came on, alarm came on. Restarted Engine. PO100 came up. Engine went into limp mode.

Checked positives and negatives, checked all terminals

Any ideas.

I changed my MAF sensor recently. While searching for the part I found that many suppliers are quoting the wrong MAF sensor for the 2.2 Puma. Many are selling the sensor for the earlier 2.4 Puma. Mine was a Ford item part number 8V21 12B579 AA which matches LR part number LR 019830. This was used from chassis numbers starting CA onwards. (The earlier one up to Chassis BA999999 was ford part number 6C11 12B579 AA, LR part number MHK 501040). They look similar but the earlier one has a square end and the later one has a curved end. Check you have the correct sensor. If it is the correct one is it a cheap chinese one or a pukka make? (my original one was a Ford item factory fitted and marked FoMoCo).
Check the voltage in your battery, sounds like it is knackered and not holding charge. A faulty alternator would show a fault code on diagnostics and as you don't say you have a fault code I would rule that out as a cause.

First thing is to check if your battery is any good, it may be its not holding charge or being charged,

As a second thought, after you changed the Maf sensor did you clear the fault code in the ECU? Or is it still showing the "old" fault code? As Scooby says check your car battery first.