JB+ Thumbs Down
Thread Starter
Member
Joined: Feb 2025
Posts: 156
Likes: 50
W204 C250 Sport (AMG Package with Pano Roof)
JB+ Thumbs Down
After changing plugs, coil packs and valve cover (OE), I fitted a JB+ tuner. It was a short experience for I got over boost related CEL, driving down my drive!
I cleared codes, set the JB+ to minimum, and still got CEL and limp home zero boost. I'm sending it back.
Has anyone got experience with Race Chip?
@antboii How has the Racechip experience been for you?
I cleared codes, set the JB+ to minimum, and still got CEL and limp home zero boost. I'm sending it back.
Has anyone got experience with Race Chip?
@antboii How has the Racechip experience been for you?
Joined: Nov 2016
Posts: 7,847
Likes: 3,499
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Joined: Nov 2016
Posts: 7,847
Likes: 3,499
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
How do you know that?
All I know is what the OP posted. If someone is going to ask for help or make a comment, it iscourteous essential to identify the vehicle that has the problem. Otherwise, we are left guessing and many folks won't bother.
All I know is what the OP posted. If someone is going to ask for help or make a comment, it is
Last edited by JettaRed; Jun 1, 2025 at 08:07 AM.
Senior Member
Joined: Mar 2023
Posts: 374
Likes: 112
C230K
After changing plugs, coil packs and valve cover (OE), I fitted a JB+ tuner. It was a short experience for I got over boost related CEL, driving down my drive!
I cleared codes, set the JB+ to minimum, and still got CEL and limp home zero boost. I'm sending it back.
Has anyone got experience with Race Chip?
@antboii How has the Racechip experience been for you?
I cleared codes, set the JB+ to minimum, and still got CEL and limp home zero boost. I'm sending it back.
Has anyone got experience with Race Chip?
@antboii How has the Racechip experience been for you?
“Adjustment:
The tune ships preset for most DME versions, which is approximately 50% on the internal dial. But due to car to car variance adjustment may be necessary. If the dial is set too high the vehicle will experience "reduced power" conditions where the gas pedal feels dead until you restart the car, and an over-boost code may be triggered. If you experience either of these conditions then lower the dial by 10% until they subside. To do this remove the two screws exposing the JB+ circuit board, and use a small screwdriver to turn the dial towards the "MIN" setting. Note even at the MIN setting the tuner is still adding horsepower. For OEM performance levels remove the tuner completely.“
https://cdn.shopify.com/s/files/1/08...12755747617271
Trending Topics
MB World Stories
The Best of Mercedes & AMG
New Mercedes-AMG SUVs Arrive With NEW V8 Engine: 12 Things You Need to Know
Verdad Gallardo
8 Oddball Mercedes Ideas That Actually Made it to Production
Verdad Gallardo
Dubai Tuner Gives the Mercedes G-Class An Entirely New Look
Verdad Gallardo
Six Gift Ideas Your AMG Loving Dad or Grad Will Cherish
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
Thread Starter
Member
Joined: Feb 2025
Posts: 156
Likes: 50
W204 C250 Sport (AMG Package with Pano Roof)
Have you tried making adjustments according to the installation guide?
“Adjustment:
The tune ships preset for most DME versions, which is approximately 50% on the internal dial. But due to car to car variance adjustment may be necessary. If the dial is set too high the vehicle will experience "reduced power" conditions where the gas pedal feels dead until you restart the car, and an over-boost code may be triggered. If you experience either of these conditions then lower the dial by 10% until they subside. To do this remove the two screws exposing the JB+ circuit board, and use a small screwdriver to turn the dial towards the "MIN" setting. Note even at the MIN setting the tuner is still adding horsepower. For OEM performance levels remove the tuner completely.“
https://cdn.shopify.com/s/files/1/08...12755747617271
“Adjustment:
The tune ships preset for most DME versions, which is approximately 50% on the internal dial. But due to car to car variance adjustment may be necessary. If the dial is set too high the vehicle will experience "reduced power" conditions where the gas pedal feels dead until you restart the car, and an over-boost code may be triggered. If you experience either of these conditions then lower the dial by 10% until they subside. To do this remove the two screws exposing the JB+ circuit board, and use a small screwdriver to turn the dial towards the "MIN" setting. Note even at the MIN setting the tuner is still adding horsepower. For OEM performance levels remove the tuner completely.“
https://cdn.shopify.com/s/files/1/08...12755747617271
Thread Starter
Member
Joined: Feb 2025
Posts: 156
Likes: 50
W204 C250 Sport (AMG Package with Pano Roof)
Joined: Nov 2016
Posts: 7,847
Likes: 3,499
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
@gav24v do you have a scanner that lets you read realtime boost? Or can you hook up a mechanical boost gauge (temporarily) to see actual boost? I don't know what normal boost is for your engine, but there is chance your JB+ device is defective. Normally boost only occurs under load. Backing out of your drive should not load the engine unless it was a steep uphill driveway. Can you view your wastegate actuator? If so, have someone rev the engine and see if it moves at all.
Thread Starter
Member
Joined: Feb 2025
Posts: 156
Likes: 50
W204 C250 Sport (AMG Package with Pano Roof)
@gav24v do you have a scanner that lets you read realtime boost? Or can you hook up a mechanical boost gauge (temporarily) to see actual boost? I don't know what normal boost is for your engine, but there is chance your JB+ device is defective. Normally boost only occurs under load. Backing out of your drive should not load the engine unless it was a steep uphill driveway. Can you view your wastegate actuator? If so, have someone rev the engine and see if it moves at all.
I was doing about 15mph on the drive and in 2nd gear. On the min setting the CEL came on when on the subdivision at about 20mph.
Joined: Nov 2016
Posts: 7,847
Likes: 3,499
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Let's hope that the CEL was a false positive due to the JB+ device messing with the electronic signals. If you were truly overboosting, you would feel it. I had a 2000 Audi A4 wtih the 1.8T and had the vacuum line that controlled the wastegate fail and ended up blowing the engine under slight acceleration. Fortunately, Mercedes has the wastegate to fail open.
Thread Starter
Member
Joined: Feb 2025
Posts: 156
Likes: 50
W204 C250 Sport (AMG Package with Pano Roof)
Let's hope that the CEL was a false positive due to the JB+ device messing with the electronic signals. If you were truly overboosting, you would feel it. I had a 2000 Audi A4 wtih the 1.8T and had the vacuum line that controlled the wastegate fail and ended up blowing the engine under slight acceleration. Fortunately, Mercedes has the wastegate to fail open.
