HZJ105 glow plug light

[RangerDownUnder]

I have a 2004 105-series with a 1HZ and I noticed today that the glow plug light on the instrument cluster comes on while the engine is running.

It comes on as usual when I first turn the key, goes out after several seconds as usual and then I start the engine as usual. However, unusually, after several seconds once the engine is running, the light will come on again and stay on until I turn the car off.

Ideas as to what the problem is? And will driving it for potentially up to several days until I can get it to a mechanic cause any damage?

 

[RangerDownUnder]

Didn't have anything to do with the glow plugs. Apparently on this model the glow plug light acts a check engine light and it ended up being a vacuum switching valve that wouldn't open. Replaced the valve and no more light on the cluster.

 

[Nancythetroop]

Didn't have anything to do with the glow plugs. Apparently on this model the glow plug light acts a check engine light and it ended up being a vacuum switching valve that wouldn't open. Replaced the valve and no more light on the cluster.

Hey RangerDownUnder, it looks like I may have the same issue as you did! How did you confirm that it was a vacuum switching valve? I’ve removed each valve and tested them using my battery and each one is clicking so would appear that they are all working! But the issue is still there and it makes sense to me that it would be related to the switching valve! Are you able to explain to me how you diagnosed that the valve was not opening? Thank you!

 

[Archi]

I have the same problem. Took the. Car to Toyota dealer. They couldn’t fix it. Had fault codes that don’t relate to my 2004 HZJ105 with 1HZ. Took the car to an auto electrician they thought it was the EGR ECU. Replaced ECU with second hand unit. Light still on. Did you fix your problem?

 

[Nancythetroop]

I have the same problem. Took the. Car to Toyota dealer. They couldn’t fix it. Had fault codes that don’t relate to my 2004 HZJ105 with 1HZ. Took the car to an auto electrician they thought it was the EGR ECU. Replaced ECU with second hand unit. Light still on. Did you fix your problem?

Hey Archi, still in the process! Took mine to a Toyota 4wd specialist and they reckon it’s a broken earth wire (don’t quote me on this could be getting a few details muddled) to one of the switching valves so even though the switching valve itself is working, its intermittent while driving. Have it booked in with an auto electrician tomorrow that they recommended. They said it’s pretty rare for those emission ECUs to go bust so they didn’t think that was it. They did read the codes with the TE1 and E1? and said it was code 41 that was being thrown. Basically what I’ve gathered is that in the later 1hzs, when they needed to add the EGR systems, they put that ecu which controls I think three sensors, and the four switching valves and it also acts as the timer for the glow plugs because the mechanics did try just disconnecting the ecu but then the glow plugs went. I reckon that makes sense that then the “engine light” would be the coil light on the cluster, cause if the ecu is already connected up to the coil light then you’d just use that light for codes as well! So I suppose if it’s not the ecu that’s causing the issue, then process of elimination, you’d think it’s have to be one of those other elements or wiring. The other thing my mechanic did was shove a ball bearing into one of the vacuum lines to block off the system. I was noticing that my troopy was stuttering or having flat spots when under load, and so it was a good test to see if those went away when the EGR was blocked off. Thank goodness it seems that the car is performing muuuuch better now with that ball bearing in place which I suppose in theory should also point to it being something in relation to either the sensors, valves, wiring or vacuum lines. Anyway! Apologies if I’ve got some wording or info wrong! Anyone feel free to correct me on terminology and what not! This has been a very frustrating but interesting issue, definitely learning a lot but hoping it gets resolved soon!