TD5 issue.

[Bohica]

Problem of the day.


It is a 1999 Land Rover Defender TD5 and I need someone to test and repair as necessary the ECU part number MSB101170.


It has all the classic signs of ECU failure with engine starting then stopping immediately and error messages such as Topside Switch Failed Post Injection and Pre Injection along with Peak Charge Short and Open Circuit Detected errors recorded for all 5 injectors. There is no oil in the ECU plugs. The injector wiring loom under the rocker cover has been replaced and the loom from the ECU to injector plug has been checked for integrity as well as resistance and shorts. The 85V output from the Injector Common 1 and 2 output (pins A22 and A23) drops to 0V just before the engine stops. CPK has been replaced although the old one was OK. This has been checked and a signal is transmitted to pin A13. Fuel pressure has been measured and is only slightly below spec.

[Blknight.aus]

board dry jointing, it might also be a short in the supply to the ecu grounding the feed to the ecu.

[John_D4]

Good time to remap it maybe?

[sierrafery]

That ''topside switch" thing is about a RC charging circuit within the ECU which contains those two big capacitors and some resistors, a circuit like this has a transient response time which can be shorter or longer hence the pre or post injection thing... the gist is that once a "topside switch failed ..." fault is current(regardless that it's pre or post injection) there is a problem with the capacitor(s), with a resistor or with the PCB so you can't rely on that ECU anymore cos it can cut out while driving unexpected or it can become unstartable so better get hold of a replacement ECU or send your's to a ECU repair specialist ASAP. .... possible symptoms described better here Defender ECU problem (http://www.ecutesting.com/land-rover/land-rover-defender-discovery-td5-ecu-fault.html)

[maxperformance]

What tool did you use to pull out all the fault codes? Could the tool clear any faults it found?

I haven't had any Nanocom for my TD5 but recently we used a MAXI Tool scanner which could diagnose many sections in a TD5 (either fault codes or live data) in both Manual and Auto, also it could clear a lot of fault codes stored inside the ECU.

[Lemo]

I'd suggest getting another ECU, maybe a NNN and get a remap:burnrubber:

[dfendr]

I have a1999 defender Td5 Ecu And a nanocom
if you want to try another ecu to confirm your diagnosis