Skip the auto shop - Our mechanics make house calls

Q: Fuel rail pressure is all over the place and the truck bucks badley going down the road. Only code that comes up is P215a.

asked by on

Fuel rail pressure is all over the place and the truck bucks badley going down the road. Only code that comes up is P215a. The speed sensor on rear differential was just replaced. This all started happening right after I blew the serpentine belt and replaced my powersteering pump

My car has 140000 miles.
My car has an automatic transmission.

The fuel pressure will fluctuate when the motor is bucking. The trick is knowing if the engine is bucking because of fuel pressure, or is the fuel pressure erratic because of the engine bucking. Usually it has nothing to do with fuel pressure. The fuel rail pressure on a diesel is created by the injection pump, which on a diesel engine changes speeds with engine RPM. So I would expect to see fuel rail fluctuation like this.

Your code indicates there is a possible problem with the CAN (computer area network) that monitors and controls the ABS system. The ABS, the TCM (transmission control module) and the PCM (powertrain control module) all talk with each other over this network. To diagnose this system you will need a scanner to monitor the data from these computers. A scanner isn’t the same as a code reader.

It isn’t a common problem for this system to cause drivability issues, but since this code brings into question the CAN system, which can affect every module on the truck, it is something that should be considered. The most common failure for this vehicle is a fuel injector. With the scanner connected, you need to look at the misfire counters for each cylinder. If one is showing misfires but the others are not, you can suspect that injector is faulty.

Injectors are expensive, so I wouldn’t go out an buy one without some additional diagnosis, but this should get you started. If you still need assistance, a certified mobile mechanic from YourMechanic can visit your home or office to inspect your truck’s bucking issues.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  • Home
  • Questions
  • Fuel rail pressure is all over the place and the truck bucks badley going down the road. Only code that comes up is P215a.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I have oil dripping from the steering damper all the way back to the transmission

I hear you, tracing oil leaks is hard! I suspect as you do that the leak is at the "nose" or front of the engine (possibly at the front crankshaft seal), and the higher oil pressure at road speed and...

Q: Advance Trac dash light comes on and the brakes are applying.

Hi there. When the Advanced Trac light comes on and then the brakes are being applied, this means that the traction control system is active. The traction control is designed to apply the brakes to a wheel when the wheel...

Q: Grinding noise front passenger tire, 2010 Nissan Versa

Hello. Grinding noises from a wheel are usually the result of worn brakes or wheel bearings. If the noise began after hitting a pot hole, then it may be possible that the wheel bearing was damaged form the impact. The...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...