Skip to content
Language: EN
Download

P0170: Fuel trim out of limits (bank 1)

The ECU is having to correct the bank 1 mixture so much that it has reached its limit. Usually an air leak, the air flow meter or fuel supply.

Code P0170 at a glance
CodeP0170
SystemEngine and transmission
GroupP01xx, Air and fuel metering
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P0170 means

The ECU constantly adjusts the amount of fuel based on the oxygen sensor reading; this correction is called fuel trim. This code means the correction on bank 1 has gone to an extreme, without saying whether the mixture is lean or rich. On inline engines, bank 1 is the whole engine.

Most common causes

  • Air leak from a vacuum hose, the intake hose or the manifold gasket
  • Dirty or faulty air flow meter misreading the air
  • Exhaust leak ahead of the oxygen sensor
  • Wrong fuel pressure from the filter, pump or regulator
  • Dirty or leaking injectors
  • Upstream oxygen sensor giving false readings

Symptoms

  • Engine warning light on
  • Higher fuel consumption than usual
  • Rough idle or hesitation
  • Lack of power or harder starting

Can you drive with P0170?

With care You can drive, but with the mixture out of step the engine uses more fuel and, if left, it can damage the catalytic converter. Have it checked soon.

How to check it

Watch the short and long term fuel trims for bank 1 in live data. Large positive values mean too little fuel or too much air; large negative values mean the opposite. Noting whether they change between idle and higher revs is very helpful for the garage.

How to read and clear P0170 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0170 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0170 is a generic code, so it means the same on any make, for example on Abarth, Alfa Romeo, Cupra, Jeep, Nissan, Škoda. See what Final OBD does on your car in makes and models.

What does code P0170 mean?

The ECU constantly adjusts the amount of fuel based on the oxygen sensor reading; this correction is called fuel trim. This code means the correction on bank 1 has gone to an extreme, without saying whether the mixture is lean or rich. On inline engines, bank 1 is the whole engine.

Can you drive with P0170?

You can drive, but with the mixture out of step the engine uses more fuel and, if left, it can damage the catalytic converter. Have it checked soon.

How do you clear P0170?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0170 comes back.