Crank but No Start and No Comms with ECU via OBD2 port - 1999 Landcruiser (1 Viewer)

[Igoteyedeas]

Hey all, after pouring through all of the threads in the 100-series section around immobilizer, EFI fuse/relay and other no-start issues, I've still found myself stuck.

A few days ago I drove the truck to a trailhead, and it had no issues. I get back, load the truck up and go to start it only to find that it will crank, but not start. Tried replacing the EFI fuse with a fresh 25a fuse since I had an extra one, but nothing. Checked for fuel pressure at the (new) fuel filter and it has pressure. Battery has good voltage. The real head scratcher is that the security light in the center console stops blinking when I insert my key, so the immobilizer is at least recognizing the key.

I've gotten to the point where I had it towed to a shop to see if it was a quick fix, and of course it's not, but they did provide some extra data points to help troubleshoot. That said, I must admit this is a bit over my head as I've never experienced an issue quite like this, so hoping that someone in the community has faced a similar issue and might have some insight.

To outline the current data points I have:
• Security/immobilizer light turns off when key is inserted
• EFI fuse replaced with 25a
• Have not replaced EFI relay, but that seems more of a fix when you immobilizer is not recognizing the key, correct?
• OBD2 port is not communicating with any tools. Even the shop's very expensive diagnostic tool gets intermittent comms from the port? When the shop is able to get it connect, they can fully clear/reset my ECU and the truck will start for 2-3 times after, but then goes back to the same issue.
• Shop replaced crankshaft position sensor to no avail
• No codes or dash lights
• Fuel pressure is good (fuel filter is new)
• Battery is good

I know these types of gremlins can be extremely difficult to track down, bu I'm hoping that some of you have had a similar issue and might be able to share your experience so that I have a place to start troubleshooting. Thank you in advance for any insights you all might be able to offer.

For reference: Some of the threads I've poured through:
• 1999 UZJ100 Intermittently Drops Dead
• 100 series cranks but won't turn over / start (includes all of the threads linked to in this post)

For reference: Some recent work that's been done to the truck:
Recent work that's been done to the truck (just incase it's relevant):
• Changed all dash/cluster bulbs to LED
• Front end refresh including brakes, wheel bearings, control arm bushings, sway bushings, tie-rod ends, etc.

 

[cjmoon]

The not communicating with the computer makes me think the computer could be the bad apple. I e got spare ECU’s if you need one. From 2 part outs I’ve done.

 

[cjmoon]

I had a crank no start and no codes. It ended up being my crank position sensor. Seems to be a common issue on the 4.7.

 

[Igoteyedeas]

I had a crank no start and no codes. It ended up being my crank position sensor. Seems to be a common issue on the 4.7.

That's great feedback, and I haven't gone that route of the crank position sensor as I troubleshoot. **EDIT: My shop actually did try swapping in a new crankshaft position sensor but it didn't help**

The intermittent OBD2 port issue makes me think the ECU might be on the fritz, in which case I would definitely like to purchase one of your extras. I need to look into different ECU's by year, but I'm assuming most of the 98-01 ECU's are the same, regardless of options like rear diff lock, rear a/c, etc?

 

[mitchjohnson000]

Bunch of ways to diagnosis this. I'd start by taking a multi-meter and trying to narrow down the possibilities. Easier and cheaper than just replacing sensors/ecu's. If you don't feel comfortable reading the factory wiring diagram I'd recommend taking it to a different shop with more experienced mechanics. 100 series have relatively simple wiring that a good mechanic should be able to diagnosis without a code reader.

1. Check that ECU is getting power from the battery.
2. Check that ECU is getting power from IG1/hot-run setting on the key
3. Manually jump start the fuel pump. Put 12v on the fuel pump relay and listen for it and document fuel pressure.
4. Check for spark.
5. Check for janky aftermarket wiring such as Alarms/Lights that could be causing a grounding issue.

Replacing an ECU is annoying since you have to reprogram your key, and TBH if this shop can't diagnosis this I would NEVER let them put in an ECU as a hail mary.

Here is FWD Box

 

[Igoteyedeas]

Bunch of ways to diagnosis this. I'd start by taking a multi-meter and trying to narrow down the possibilities. Easier and cheaper than just replacing sensors/ecu's. If you don't feel comfortable reading the factory wiring diagram I'd recommend taking it to a different shop with more experienced mechanics. 100 series have relatively simple wiring that a good mechanic should be able to diagnosis without a code reader.

1. Check that ECU is getting power from the battery.
2. Check that ECU is getting power from IG1/hot-run setting on the key
3. Manually jump start the fuel pump. Put 12v on the fuel pump relay and listen for it and document fuel pressure.
4. Check for spark.
5. Check for janky aftermarket wiring such as Alarms/Lights that could be causing a grounding issue.

Replacing an ECU is annoying since you have to reprogram your key, and TBH if this shop can't diagnosis this I would NEVER let them put in an ECU as a hail mary.

Here is FWD Box

Mitch,

Massive thank you for the resource and tips. I'm going to start going down this list and see where that leaves me.

 

[Igoteyedeas]

To those that might be curious, ended up sending the ECU off to SIA Electronics for diagnostics. Just got the call today that the ECU is not repairable due to a CPU failure. Not entirely sure how that happened as the ECU looked great (including the PCB board inside), but it did. Having the core returned to me, in the event it serves any use.

So now onto the mission of finding another ECU and figuring out how to clone it for my vehicle. If anyone has suggestions or experience do that, let me know!

 

[gregnash]

@Mauser may be able to help you find an ecu.

 

[Igoteyedeas]

@Mauser may be able to help you find an ecu.

Open and willing for any help! I've been looking at companies, such as Flagship One, that offer pre-programmed ECU's, but have no idea of what to expect from that. To make things more complicated, the reviews for companies like these range from "these guys are the worst" to "worked like a charm" so you never know what to expect.

I'm sure I'd still have to have a locksmith program the new ECU to my existing master key (or take the immobilizer EPROM from my existing ECU), but is there anything else I need to be aware of?

 

[Mauser]

What is the part number of your ecu? I may have one.

 

[Igoteyedeas]

What is the part number of your ecu? I may have one.

My part # is: 89666-60261

Let me know and I'll be happy to send money over to cover parts and shipping!

If you do have one, is it as simple as getting it programed by a locksmith and plugging it into the truck, or are there additional items that need to be "synced" with the truck?

 

[Mauser]

My part # is: 89666-60261

Let me know and I'll be happy to send money over to cover parts and shipping!

If you do have one, is it as simple as getting it programed by a locksmith and plugging it into the truck, or are there additional items that need to be "synced" with the truck?

I've got one ready to go. Send me a message. I should be able to get it in the mail tomorrow.

It is virginized. It will come in auto registration mode. This will allow you to add 2 master keys and one valet. You just have to insert them into the ignition switch for a second.

Here is a video of my 98 LX. Adding keys is the same for the LC

 

[haryv]

Hey all, after pouring through all of the threads in the 100-series section around immobilizer, EFI fuse/relay and other no-start issues, I've still found myself stuck.

A few days ago I drove the truck to a trailhead, and it had no issues. I get back, load the truck up and go to start it only to find that it will crank, but not start. Tried replacing the EFI fuse with a fresh 25a fuse since I had an extra one, but nothing. Checked for fuel pressure at the (new) fuel filter and it has pressure. Battery has good voltage. The real head scratcher is that the security light in the center console stops blinking when I insert my key, so the immobilizer is at least recognizing the key.

I've gotten to the point where I had it towed to a shop to see if it was a quick fix, and of course it's not, but they did provide some extra data points to help troubleshoot. That said, I must admit this is a bit over my head as I've never experienced an issue quite like this, so hoping that someone in the community has faced a similar issue and might have some insight.

To outline the current data points I have:
• Security/immobilizer light turns off when key is inserted
• EFI fuse replaced with 25a
• Have not replaced EFI relay, but that seems more of a fix when you immobilizer is not recognizing the key, correct?
• OBD2 port is not communicating with any tools. Even the shop's very expensive diagnostic tool gets intermittent comms from the port? When the shop is able to get it connect, they can fully clear/reset my ECU and the truck will start for 2-3 times after, but then goes back to the same issue.
• Shop replaced crankshaft position sensor to no avail
• No codes or dash lights
• Fuel pressure is good (fuel filter is new)
• Battery is good

I know these types of gremlins can be extremely difficult to track down, bu I'm hoping that some of you have had a similar issue and might be able to share your experience so that I have a place to start troubleshooting. Thank you in advance for any insights you all might be able to offer.

For reference: Some of the threads I've poured through:
• 1999 UZJ100 Intermittently Drops Dead
• 100 series cranks but won't turn over / start (includes all of the threads linked to in this post)

For reference: Some recent work that's been done to the truck:
Recent work that's been done to the truck (just incase it's relevant):
• Changed all dash/cluster bulbs to LED
• Front end refresh including brakes, wheel bearings, control arm bushings, sway bushings, tie-rod ends, etc.

This Thread is over a month did the shop find the problem?

 

[Igoteyedeas]

This Thread is over a month did the shop find the problem?

The shop gave up after about 2-3 days with the diagnosis that it was likely the ECU. While often times I've heard that can be a cop out from a shop (aka they just can't figure it out), I sent the ECU off to SIA Electronics for diagnosis, and it came back that the CPU was on the fritz and that the ECU was not repairable. My best guess is that the failing CPU prevented the ECU from holding a memory, so it wouldn't recognize my keys, thus causing the immobilizer to prevent the truck from starting.

I'm currently waiting for a replacement ECU to arrive (massive thank you to Mauser), so I can plug it in and see if I can get it running again. I'll update the thread as soon as I'm able to.

I'll tell you, a month without my TLC is painful. Never mind that it's my daily—it's my baby!

 

[haryv]

The shop gave up after about 2-3 days with the diagnosis that it was likely the ECU. While often times I've heard that can be a cop out from a shop (aka they just can't figure it out), I sent the ECU off to SIA Electronics for diagnosis, and it came back that the CPU was on the fritz and that the ECU was not repairable. My best guess is that the failing CPU prevented the ECU from holding a memory, so it wouldn't recognize my keys, thus causing the immobilizer to prevent the truck from starting.

I'm currently waiting for a replacement ECU to arrive (massive thank you to Mauser), so I can plug it in and see if I can get it running again. I'll update the thread as soon as I'm able to.

I'll tell you, a month without my TLC is painful. Never mind that it's my daily—it's my baby!

Yeah the fact that the ECU was not returning any kind of codes was probably are they suspected it would be the ECU. I'm not going to release a website that I use to obtain answers but it has thousands and thousands of Master techs that get together and help to solve each other's problems. If you provided me with all of the symptoms I would charge you a certain amount of money if of course you had the experience to troubleshoot. I would probably charge your shop but the chances of getting an accurate answer within a very short. Of time would be much faster than what your shop could I have found the answer.

 

[Igoteyedeas]

Just updating the thread to note that the new ECU supplied by @Mauser did the trick! Truck fired right up and continues to work. Never in my years have I experienced a bad ECU on any of my cars (many of which are well over 100K miles). (thank you @gregnash for tagging him!)

Grateful for the expertise on this forum as it is what helped me get to the bottom of this. Thanks, Mud!

 

[gregnash]

Just updating the thread to note that the new ECU supplied by @Mauser did the trick! Truck fired right up and continues to work. Never in my years have I experienced a bad ECU on any of my cars (many of which are well over 100K miles). (thank you @gregnash for tagging him!)

Grateful for the expertise on this forum as it is what helped me get to the bottom of this. Thanks, Mud!

AWESOME!!! So glad it worked out for you. I tagged @Mauser as a long shot, but knew he had done some work with virginizing ECUs in the past.

 

[YotaNV]

Glad I went through this thread, I'm literally waiting for the ECU to arrive. I took it to a shop, they did a thorough diagnosis, we replaced battery, starter, alternator and ordered ECU. We believe the alternator shorted and fried ecu. Ill try to get the video from the mechanic, but there was current still running through the vehicle unplugged. I will update once ECU is installed, but identical scenario.

 

[EJ Kestler]

Glad I went through this thread, I'm literally waiting for the ECU to arrive. I took it to a shop, they did a thorough diagnosis, we replaced battery, starter, alternator and ordered ECU. We believe the alternator shorted and fried ecu. Ill try to get the video from the mechanic, but there was current still running through the vehicle unplugged. I will update once ECU is installed, but identical scenario.

Hi - where did you get the ECU from?

 

[Mauser]

Hi - where did you get the ECU from?

Are you needing an ecu? For what year?