2002 HDJ101 1HD-FTE crank no start

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Darren Fraser
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2002 HDJ101 1HD-FTE crank no start

Post by Darren Fraser »

Hi Guys
I thought I would share this because I really struggled to find ANY wave form for a HDJ101 Toyota Landcruiser spill control valve.
HDJ101 LANDCRUISER 1HD-FTE SPILL VALVE BAD AFTER GOOD.png

Darren Fraser
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Posts: 44
Joined: Sat Jul 18, 2020 7:45 am

Re: 2002 HDJ101 1HD-FTE crank no start

Post by Darren Fraser »

1hd-fte SPV+ known bad.png
I realise I may have posted this in the wrong forum, in that there is not a detailed explanation of the case study?

Its more a study of a particular waveform where the fault cleared very briefly and then went back into a crank no start condition.

Anyway, a bit of history in the job was that the vehicle vehicle was towed into us with the complaint of a crank no start condition, and that the Ignition fuse was blown, had been replaced and the vehicle would start after the fuse was replaced, run for a few seconds and cut out again leaving the Ign1 fuse blown again.

Inspection of the Ign1 fuse circuit revealed that it was a 12v supply to the ECM through a N/C contact in the stoplight switch and was shorting constantly with KOEO even before cranking.

Stoplight switch wiring was melted and fused together, we asked the customer for the original fuse and discovered it had been bridged out, hence the burnt wiring.

We isolated the wires and insulated them and discovered the original short was on the stoplight N/O contact which was a short to ground on the stoplight wiring at the rear of the vehicle, which was sorted out, but we still had a crank no start condition even after repairing the stop light wiring.


I was out of the shop the next day and was proudly informed that the problem had been solved and the vehicle was now running, which it was. I asked what was wrong and was told it was a loose connection on the ECM relay which was not pushed all the way home. Feasable, but not proven!

Anyway, we took it for a 20km test drive and it was fine until the last 500m where I applied the brakes to turn into our workshop and the vehicle died and was back in crank no start condition.

First tests were powers and grounds to the ECM especially the spill valve relay which also powers up the MDU spill valve driver.

All powers and grounds were good (including the stoplight fuse which was behaving itself), but still had the crank no start condition.

We then decided to scope the MDU inputs and outputs and this was the result.
HDJ101 1HD-FTE crank no start spill valve open circuit.png


The ECM signal into the MDU commanding a spill control was good, and the MDU was responding with a 150V spike (which I presume is to needed to provide sufficient force to open the SPCV?). However, there was no return signal (red trace)from the MDU to the ECU indicating a spill control event, AND more interesting was there was no evidence of current flow in the spill valve coil.

We then checked the resistance of the spill valve circuit and found it to be open. Further checks revealed that someone has damaged one of the terminals in the spill valve solenoid plug on the injector pump which resulted in an intermittent open circuit of the solenoid circuit.

We were very fortunate to get a very brief glimpse of the vehicle trying to start (just once out of about 100+ attempts) and I saw what the voltage trace and return signal should look like if current flows. Prior to this I had no clue as to what a known good 1HD-FTE MDU out put wave form looked like, so this capture was a major breakthrough for me.
1hd-fte SPV+ known bad.png
We repaired the plug and this was the final fix waveform.
HDJ101 1HD-FTE SPCV command from MDU known good.png
It very nicely shows spill valve PWM controls, the amperage draw in proportion to the voltage, and the previously missing return signal from the MDU to the ECU on the red trace.

I hope this helps someone in future, and I want to just thank you all at Pico once again for your commitment to the motor industry.

Steve Smith
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Re: 2002 HDJ101 1HD-FTE crank no start

Post by Steve Smith »

Thank you for posting Darren, this would have helped so much when I first encountered such an issue with an LC Amazon

A bulletin was released post production to rectify this connector issue (replacement and bonding) which you have captured here.

Rest assured you are helping someone somewhere and if you could upload your captures to the waveform library that will most certainly reach those in need

Take care.....Steve

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