Shimano EP8 Motor Turns Off After 18 Seconds

johnf0246

Active member
Jan 22, 2021
139
71
Sedona, Arizona
I have an EP8 motor on my Pivot Shuttle. The Ebike has over 5,000 miles on it and has been trouble free up to this point. Recently I was on a mountain bike ride when my bike came to a stop while climbing up a hill section. I looked at the display and it was blank.

I pressed the start button and the bike display lighted up with no error codes. So I started back up the hill I was riding on. After a couple seconds the bike suddenly stopped again with a blank display.

I was about 5 miles from home and decided to head home. Every 18 seconds the bike would turn off and I would press the start button while still moving. The display would light up and I would press the power button and start pedaling again. Each time the bike would power up I would count to 18 and the bike power would shut off again.

I made it home over 5 miles no problem other than turning the power back on every 18 seconds.

When I got home I called the Shimano Trouble Shooting Department and spoke with the tech on duty. When I told him my problem he indicated he had never heard of my issue and to go to the nearest bike shop that services Shimano motor Ebikes. He said they would plug my bike into there computer and look for error codes.

I followed his suggestion and drove directly to the local bike shop. When I got to the shop the mechanic thought my magnetic rotor maybe faulty. He put on a new Shimano Ice Tech rotor and pressed the power button. Since the bike was up on the bike stand he spun the crank arm and the rear wheel started spinning at a fast RPM. The display stayed on for 18 seconds and powered down. Apparently my rotor was not defective. The bike shop mechanic did not hook my bike to their shop computer. He said the Monday mechanic was the most experienced in motor dianogstics and I should leave my bike for his evaluation. I did as he suggested.

I have one concern. I have previously installed the $1 ST Unlocker software to my EP8 motor when the bike had about 100 miles on it. I had installed the software to see if I could adjust the rear wheel tire size to 27.5” from 29”. My bike came as a 29er, but I changed it to a mullet (27.5) in the rear. I was unable to make the change since the cheap version doesn’t have the change in wheel size feature. I didn’t buy the more expensive software version that supports changes in wheel circumference and direstricting. I didn’t need derestricting since my bike was purchased in the US and I live in the US. My Ebike doesn’t have assist over 18 MPH and I have lived with that slower than maximum 20 MPH assist I could get with a software update.

Is the inexpensive ST Unlocker software installed on my EP8 motor going to void the warranty?

Any help with my situation would be appreciated.
 
Last edited:

johnf0246

Active member
Jan 22, 2021
139
71
Sedona, Arizona
I have an EP8 motor on my Pivot Shuttle. The Ebike has over 5,000 miles on it and has been trouble free up to this point. Recently I was on a mountain bike ride when my bike came to a stop while climbing up a hill section. I looked at the display and it was blank.

I pressed the start button and the bike display lighted up with no error codes. So I started back up the hill I was riding on. After a couple seconds the bike suddenly stopped again with a blank display.

I was about 5 miles from home and decided to head home. Every 18 seconds the bike would turn off and I would press the start button while still moving. The display would light up and I would press the power button and start pedaling again. Each time the bike would power up I would count to 18 and the bike power would shut off again.

I made it home over 5 miles no problem other than turning the power back on every 18 seconds.

When I got home I called the Shimano Trouble Shooting Department and spoke with the tech on duty. When I told him my problem he indicated he had never heard of my issue and to go to the nearest bike shop that services Shimano motor Ebikes. He said they would plug my bike into there computer and look for error codes.

I followed his suggestion and drove directly to the local bike shop. When I got to the shop the mechanic thought my magnetic rotor maybe faulty. He put on a new Shimano Ice Tech rotor and pressed the power button. Since the bike was up on the bike stand he spun the crank arm and the rear wheel started spinning at a fast RPM. The display stayed on for 18 seconds and powered down. Apparently my rotor was not defective. The bike shop mechanic did not hook my bike to their shop computer. He said the Monday mechanic was the most experienced in motor dianogstics and I should leave my bike for his evaluation. I did as he suggested.

I have one concern. I have previously installed the $1 ST Unlocker software to my EP8 motor when the bike had about 100 miles on it. I had installed the software to see if I could adjust the rear wheel tire size to 27.5” from 29”. My bike came as a 29er, but I changed it to a mullet (27.5) in the rear. I was unable to make the change since the cheap version doesn’t have the change in wheel size feature. I didn’t buy the more expensive software version that supports changes in wheel circumference and direstricting. I didn’t need derestricting since my bike was purchased in the US and I live in the US. My Ebike doesn’t have assist over 18 MPH and I have lived with that slower than maximum 20 MPH assist I could get with a software update.

Is the inexpensive ST Unlocker software installed on my EP8 motor going to void the warranty?

Any help with my situation would be appreciated.
If anyone reads my original post the supposed reason for the bike shutting off after 15 seconds was a faulty Darfon 726 WH battery. It took three weeks to diagnose the problem. Wires were replaced per Shimano’s warranty department request. That didn’t work. Finally I borrowed an almost new battery from a friend and the tech said that was the problem.

Supposedly a new Darfon battery is being replaced under warranty. The battery lasted a year with 5,400 miles.
 

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