The fuel trim is a ratio of fuel to air that your engine utilizes to produce power. Your onboard Powertrain Control Module (PCM) or Engine Control Unit (ECU) is responsible for maintaining this fuel trim. This ratio is responsible for producing power efficiently as well as minimizing the pollution that your vehicle produces. Should one of your sensors or components go bad, the P0170 trouble code can rear its ugly head.
Your PCM or ECU uses a variety of sensors to accurate gauge the right amount of fuel to deliver. Your fuel system components like your fuel pump, fuel injectors, and fuel pressure regulator are vital parts to the overall equation.
Any number of these components can wear or fail. This can contribute to your vehicle running rich or lean. Either condition will trigger a Malfunction Indicator Lamp or check engine light. When this happens, you’ll need an OBDII scan tool to read the stored P0171 trouble code.
What Does P0170 Code Mean?
Should the P0170 check engine light turn on, this means that your onboard computer sees something out of wack. More specifically this relates to the Short Term Fuel Trim or Long Term Fuel Trim of your vehicle. Your ECU or PCM uses your oxygen sensor to gauge the air-fuel ratio of your vehicle.
By using the values from the 02 sensors, your computer is constantly trying to reach an efficient burn ratio. This ratio is a mixture of 14.7 to 1, otherwise known as the stoichiometric ratio. Ideal for combustion, power, and efficiency, the P0170 error code is lit when your ECU cannot reach an optimal ratio and manufacturer thresholds have been breached.
Related Error Codes to P0170
- P0171 System Too Lean
- P0172 System Too Rich
- P0173 Fuel Trim
- P0174 System Too Lean
- P0175 System Too Rich
Guides to Fix P0170 Check Engine Issues
- DTC P0171 – How To Find Intake Leaks
- DTC P0171 – How To Find Intake Leaks
- DTC P0171 – How To Replace a VQ35 Fuel Pressure Regulator
- DTC P0171 – How To Service a Cadillac ATS MAF
Symptoms of P0170
- Bad Gas Mileage
- Poor Performance
- Engine hard to start
- Hesitation during acceleration
- Engine misfire
Common Causes of P0170 Code
Leaky Fuel Injector – This is a common issue that can contribute to the failure of your ECU or PCM to maintain proper air-fuel ratio.
Intake leaks – Leaks in your intake snorkel, intake manifold or intake plenum can all cause your vehicle to run lean.
Failed Mass Air Flow Sensor – The Mass Air Flow Sensor or MAF is responsible for reading the airflow into your engine. When this unit is fouled or failing, your PCM won’t have the information it needs.
How to Fix P0170 error code
Begin by using a OBDII scan tool to read your Short Term Fuel Trim (STFT). If this value is out of wack, begin with the following steps.
Check for intake leaks – Using a spray bottle with soapy water, spray gently and carefully around your intake system. Take special care not to spray too much into your intake stream. Look for leaks in your intake system past your MAF or MAP sensor.
Check your oxygen sensors – Over time these units can foul or even outright fail. Check them for proper operation.
Check for fuel problems – Issues with your fuel injectors, fuel pump or fuel pressure regulator will all make life on your ECU tough. Check to make sure these parts are working properly.
