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Technicaldan, Technician
Category: Volvo
Satisfied Customers: 110
Experience:  Accredited
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Have a 2007 Volvo S40 2.4i. Gave dash message of "try slow

Customer Question

Have a 2007 Volvo S40 2.4i. Gave dash message of "try slow down or shift up". ran like crap misfiring. Pulled DTC P0301, P0201. Replaced the cylinder #1 ignition coil. no improvement.
JA: Sometimes things that you think will be really complicated end up being easy to fix with Volvo. The Volvo Mechanic I'm going to connect you with knows all the tricks and shortcuts. Tell me a bit more about what's going on so he can help you best.
Customer: replaced the plugs 6 months ago. did not check spark plug in cylinder #1 yet'
JA: Spark plug problems can be challenging. So many causes, some simple, some complicated. Fortunately, the mechanics we work with have tons of experience dealing with all of them. Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: already stated what i did in the previous 2 notes
JA: Is there anything else important you think the Volvo Mechanic should know about your Volvo?
Customer: its in good shape with 110k miles
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Volvo Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Volvo
Expert:  Technicaldan replied 1 year ago.


The DTC P0301 means cylinder 1 misfire condition but it doesn't necessarily mean that it is a ignition related misfire and with the presence of the P0201 DTC which points to a fault with the injector system for that cylinder, it is more likely that you have a problem with the injector or wiring for that cylinder causing the misfire and that set both codes.

BBA Reman have published a very good guide on how to diagnose P0201 faults, I feel I would be assisting you more by providing you their link rather than many lines of text.

I would expect that once the injector issue is sorted that both codes will clear.

I hope this helps you, please rate five stars :)