SL/R230: Help with SOS, P0451 & P1304 Errors
Thread Starter
Junior Member
Joined: Apr 2014
Posts: 37
Likes: 8
From: Salem, OR
2007 SL550, 2005 SLK350
Help with SOS, P0451 & P1304 Errors
Weird thing happened over the long weekend. As I was an hour into my 3 hour drive home from a long weekend camping, I got the Check Engine light so I stopped and checked the engine and the fuel filler cap. They both seemed in order.
When I started back up, I got the SOS Tele Aid inoperative message on the dash display. No big deal, since I don't use the SOS button anyway.
The car (2007 SL550) drove fine all the way home. The next day, I put my Bluetooth OBDII adapter on and ran Torque. That gave me the P0451 Powertrain as a current fault and the P1304 Powertrain fault. It says the P0451 is Evaporative Emission Control System Pressure Sensor Range/Performance.
I know this shows up a lot when the fuel cap is not on tight or is old and cracked, so I inspected and cleaned the cap. Made no difference. Maybe I need to go through a few drive cycles? In the meantime, I've ordered a replacement fuel cap.
The only thing I can find online regarding the P1304 is that the #4 cylinder is misfiring. I swapped the #4 coil pack to the #5 cylinder and expected the fault to change to P1305, but am still getting the P1304 code. Any ideas from the collective?
It seems very odd that the SOS message came up around the same timeframe. Is there something in common with the Tele Aid system and either of the two P codes? Fuse?
When I started back up, I got the SOS Tele Aid inoperative message on the dash display. No big deal, since I don't use the SOS button anyway.
The car (2007 SL550) drove fine all the way home. The next day, I put my Bluetooth OBDII adapter on and ran Torque. That gave me the P0451 Powertrain as a current fault and the P1304 Powertrain fault. It says the P0451 is Evaporative Emission Control System Pressure Sensor Range/Performance.
I know this shows up a lot when the fuel cap is not on tight or is old and cracked, so I inspected and cleaned the cap. Made no difference. Maybe I need to go through a few drive cycles? In the meantime, I've ordered a replacement fuel cap.
The only thing I can find online regarding the P1304 is that the #4 cylinder is misfiring. I swapped the #4 coil pack to the #5 cylinder and expected the fault to change to P1305, but am still getting the P1304 code. Any ideas from the collective?
It seems very odd that the SOS message came up around the same timeframe. Is there something in common with the Tele Aid system and either of the two P codes? Fuse?
Thread Starter
Junior Member
Joined: Apr 2014
Posts: 37
Likes: 8
From: Salem, OR
2007 SL550, 2005 SLK350
So here we are almost exactly 1 year later and over the same 1st weekend of July that I was making the same trip back from the same camping spot and the same CEL and P0451 / P1304 codes pop up. Maybe it's just a software bug that only occurs on the Independence Day weekend?
I don't think it's distance related, as I've driven many >1-hour trips over the past year without having the same symptom occur. Perhaps it's the precise combination of engine and air temp, fuel level, elevation, barometric pressure...
I don't think it's distance related, as I've driven many >1-hour trips over the past year without having the same symptom occur. Perhaps it's the precise combination of engine and air temp, fuel level, elevation, barometric pressure...
Super Member
Joined: Aug 2017
Posts: 520
Likes: 203
From: Scottsdale AZ
2015 SL550 & 2012 S550 4matic
And the GREMLINS that appear randomly. Seems like old codes might be getting revived based on combinations you site. Suggest clearing all codes (using DAS if possible) and see if if annual event reappears.
