J4500/E4500 Won’t Start – Retarder Applied Light Stays On

ThymeTraveler · February 10, 2025, 09:53:42 PM

I'm troubleshooting a no-start issue on my 2000 J4500/E4500 102 EL3 and could use some insight. Vin Last 5=61441

Symptoms:
Retarder Applied light stays on.
No Check Engine light on initial key turn.
No Stop Engine light on initial key turn.
No display on the VIM (Vehicle Interface Module).

Here's a video of our bus that was made by the seller. You can see all the dash lights cycle on/off, and you hear the solenoids click.
https://www.youtube.com/watch?v=lXlHuIMxkGM

What I've Done So Far:
I've been working on this for seven days here at Fort Irwin Army Base, California. Ill have to tow it to the MCI service center near Ontario Ca if I cant figure this out in the next 3 days.

When I turn the key before cranking, the dash lights up, and everything seems normal.
I've tested various components, checked fuses, and looked at wiring.
I haven't yet explored why the Retarder Applied light is staying on, so I'm focusing on that now.

Looking for Help With:
What would cause the Retarder Applied light to stay on and prevent a start?
Could this be related to a brake switch, retarder solenoid, or transmission issue?
Any known electrical gremlins that could cause these symptoms?
Any guidance would be greatly appreciated!

Thanks,
Noah

luvrbus · February 11, 2025, 04:52:23 AM

Does the shift pad light up or have a message ? ,the retarder light will come on if the fuse blows to the shift pad

ThymeTraveler · February 11, 2025, 08:16:05 AM

No, the shift pad doesn't light up. It has a faint light or you could call it a glow like it normally has so you can which buttons to push at night. It does not have the normal red letter "N" when I turn the key over.

luvrbus · February 11, 2025, 09:10:04 AM

Quote from: ThymeTraveler on February 11, 2025, 08:16:05 AM
No, the shift pad doesn't light up. It has a faint light or you could call it a glow like it normally has so you can which buttons to push at night. It does not have the normal red letter "N" when I turn the key over.

The fuse is blown outside under the drivers window powering the pad it is hard to see in the upper corner a inline fuse in a holder replace it and you will be good to go if the pad didn't fry

ThymeTraveler · February 11, 2025, 04:57:15 PM

Hi, thanks for your reply. If there is a fuse for the VIM, I can't locate it. My VIM plugs directly into a quick connect cable and then into a small relay box. My overall problem is the vehicle is a no start. MCI service center says I am not getting enough power to the ignition to be able to get power to the VIM. Today I have spent the day opening wire harness to the green quick connect on the fuse box as MCI service center says there is 3 24V wires that go to the ground that are spliced, and those splice's tender corrode, and is often the problem.

In doing this, I found one pigtail wire coming off a battery cable that was heavily oxidized. So I am now on my way back from Home Depot with a terminal connector and I'll cut it off that battery cable and go directly to the terminal.

Hopefully, this fixes the issue, as this particular wire goes straight to the fuse box.

Busted Knuckle · February 11, 2025, 06:29:24 PM

Noah, while MCI service centers are MCI and they do try to help don't put 100% in what they say.
Check that outside compartment under the window Clifford is telling you about. Clifford has forgotten more about buses than most of us will ever know! If Clifford speaks with so much confidence on a subject you can bet he's 100% had experience with it and probably more than once!
Now I'm not saying that Clifford is right on this and MCI is wrong, but don't dismiss Clifford's suggestion to FIND that inline fuse!
I personally have experienced blown inline fuses that "Tech Support" never mentioned.
Good luck with the problem wherever it is.

BK

ThymeTraveler · February 11, 2025, 07:59:10 PM

Howdy Cliffard,
Howdy Bryce,

First off, I just want to say how much I truly appreciate any and all information shared here. I feel a little guilty calling the MCI service center since I know their support is free, and I never want to waste anyone's time—time is valuable, whether it's theirs or yours here in the forum. The fact that I'm getting responses at all is amazing, considering I can barely remember to check my email, let alone stay active in a group like this. So, sincerely—thank you for taking the time to help.

I've been chasing this issue down a lot of rabbit holes, and in the 19 months we've owned this bus, we've never been in a position where we couldn't get it running. This has been a first. I also want to mention that I don't always come across well in writing—I never mean to brush off advice, and I take every bit of information seriously. I'll try everything suggested.

Update: The oxidized cable wasn't the issue. I'm still searching for this fuse in the J-Box but can't seem to track it down. Is it directly connected to the wiring harness for the VIM?

Thanks again—I really appreciate all of you.

luvrbus · February 12, 2025, 03:22:48 AM

The fuse is not in the J box I don't do good at writing either ,it just has a cap on it and is tough to find.I gave my manuals away for the J so I have no schematics to help lol I look for that fuse for 3 days myself. I don't know what color the wire is to power the shift pad.I would unplug the shift pad and use a meter or test light to see if has power if it does the pad is bad, MCI is terrible about changes to wiring and locations of the source they change the schematics like most people change socks and you are dealing with multiplex wiring system that is not for the weak

.JD at C and J in MN may could help you more than me or MCI (952)881-0034

ThymeTraveler · February 12, 2025, 11:14:38 AM

It's not in the jbox? Does that mean it is under the jbox where the Airhorn is located and the ZF servocom is? or under the left armrest control console with the vim and toggle for retarder? JD at C&J won't mind talking to a random guy in California about this issue? I have access to every single document for the bus through the NFI TIV setup/login. So I'll see if I can't trace it back from there. I'm slowly getting better at reading these electrical schematics.

DoubleEagle · February 13, 2025, 08:08:52 PM

I don't know if it would apply in this situation ay all, but I had a no start situation in a VanHool bus because the cruise control was partially on. Otherwise, pay attention to Cliff and BK.

luvrbus · February 14, 2025, 06:52:04 AM

What engine I see you have the ZF,I took it for granted you had the Allision , those came with 3 different engines ,I reread your post if the check engine light doesn't cycle through the self diagnostics test they will not start as you know they will not start if the voltage is under 10 volts on a series 60,I have trouble shooting for the Detroit and Cummins but nothing for the CAT engine

ThymeTraveler · February 15, 2025, 04:09:35 PM

Still a no go here if anyone else can provide some insight? Perhaps some other areas for me to check?

ThymeTraveler · February 15, 2025, 04:13:26 PM

Quote from: luvrbus on February 14, 2025, 06:52:04 AM
What engine I see you have the ZF,I took it for granted you had the Allision , those came with 3 different engines ,I reread your post if the check engine light doesn't cycle through the self diagnostics test they will not start as you know they will not start if the voltage is under 10 volts on a series 60,I have trouble shooting for the Detroit and Cummins but nothing for the CAT engine

I do have the Detroit diesel and the Allison. The ZF-Servocom is the steering gear - which is what allows us to turn the bus. Does anyone know of a paid telephone service I can use? a call center I can pay for that will walk me through what to check.

ThymeTraveler · February 15, 2025, 07:06:12 PM

Will the bus start if the primary and secondary brake systems are empty? Could the retarder stay engaged if it was left on, preventing disengagement due to low air pressure in the brake lines?

I think it has to be the Vim, the bus thinks it in gear.

luvrbus · February 16, 2025, 05:46:37 AM

If the engine is turning over with the switch the transmission is in neutral, the Alllison defaults to neutral ,you need to check for power at the pad without it not lighting up you cannot flash and codes to read, you need a scanner .Untied is in San Bernardino call 800-527-1637 they may know of a mobile or can tell you what is going on with the pad,MCI should be able to tell you what is interlocked on the VIM ,I know the ABS braking is interlocked to one of the VIM on the J but won't keep it from starting but will prevent the transmission from engaging, In the starting mode if a bad relay or switch drops the power to the ECM they will not start but I don't believe that is your problem the retarder light will go out if the pad light ups