Engine code: BNM - PD70
Attached is my evidence, otherwise you wouldn't believe me lol.

Bought this car a year ago, knowing it had a sensor fault. Vehicle was in limp mode, wouldn't allow me to go over 3,000rpm, and was slow(er) compared to normal. So, I got the sensor replaced promptly, and I thought the error had been resolved. Over the course of the year, I've had this fault come back again, and again. DTC shows P0726 as expected, glow plug & EML on. However, the car NEVER activates limp mode. Functionality of the engine does not change once this error triggers (no reduced power, no rev limitation etc.), and the only way to trigger it is to go above 4,000 rpm. It will NOT trigger any other way. While idling, at times (rarely), the vehicle can feel more "clattery", or to explain better, it idles rougher, and you can hear a change in the way the engine idles.

On a potentially related note, >> https://youtube.com/shorts/32a0czXYh_8 << shows throttle issues while stationary. Issue being, the revs seem to hang, and throttle response is seriously retarded (not a slur, technical definition). However, when depressing the clutch, the throttle response is as sharp and crisp as TDi's are known for.

Has anyone came across these issues before, what the hell is the issue with my seemingly dying Polo? (Check the freeze frame of when the DTC triggered EML/GPL. No reading for throttle position or engine RPM's... (??)

Note, vehicle has never been mapped. Vehicle has a straight through exhaust, and a Pod filter. No the modifications caused these issues as the issue was prevalent prior to installation.

Now, the only other thing that has been changed with this vehicle, at least electronically, was a control box for the central locking, this had an antenna, and would link up to the BCM behind the dash. The car came with a fob on the key to control this box.

(Just a note. I have no "special" tools. The only tools I have are a couple of screwdrivers and a ratchet/socket set. I do not have the ability to check resistances/connectors to test faults. I'm genuinely stumped at this issue, and NEED this car 100%. If it helps, I'm based in Central Scotland.)

PLEASE HELP.

Have you checked the plug and wiring for wear/damage?

On 27/06/2025 at 17:14, Yeti said:

Have you checked the plug and wiring for wear/damage?

The plug was replaced. However, yes, I did check the plug for damage. That was the first thing I did, thought it was maybe a broken wire or the plug not fully connected etc... However, without the plug being fully connected, the engine then doesn't start. Which automatically rules that out.