OBD-II Code
P1170
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$50–$700
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$50 (MAF clean + vacuum-leak repair) to $700 (intake gaskets + A/F sensor + labor).
P1170 is Infiniti/Nissan's A/F (air-fuel ratio) Sensor Adjustment Excessive code, set when the ECM's closed-loop trim correction at the wideband A/F sensor exceeds the allowable adjustment range — typically a +/-10-20% trim window in normal operation, and P1170 means the ECM is correcting beyond that and can't bring the actual lambda back to commanded lambda.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP1170 is Infiniti/Nissan's A/F (air-fuel ratio) Sensor Adjustment Excessive code, set when the ECM's closed-loop trim correction at the wideband A/F…
P1170 is Infiniti/Nissan's A/F (air-fuel ratio) Sensor Adjustment Excessive code, set when the ECM's closed-loop trim correction at the wideband A/F sensor exceeds the allowable adjustment range — typically a +/-10-20% trim window in normal operation, and P1170 means the ECM is correcting beyond that and can't bring the actual lambda back to commanded lambda. It's effectively a 'fuel trim out of range' code at the wideband sensor, not a hard sensor failure.
Shop ladder, cheapest first
- Smoke-test the intake — vacuum leaks are the #1 cause of P1170 on VQ-series engines, particularly at the intake-manifold gaskets, the rubber elbow between the MAF and throttle body, and the PCV grommet on the valve cover.
- Scan live data and watch the A/F sensor voltage and trim percentages at idle and at 2,500 rpm: a healthy VQ35/VQ37 wideband reads ~3.3V at stoich (lambda 1.0) with trims under +/-10%; if you see trims pinned at +20% or -20% the ECM is at its correction limit.
- Clean the MAF sensor with CRC MAF-specific spray ($12 can) — VQ-series MAFs contaminate easily and over-/under-report airflow, which causes exactly this kind of trim excursion.
- Inspect the A/F sensor itself for ceramic damage from coolant or oil contamination (head gasket weep, valve cover leak) — a contaminated wideband reads erratically and can cause the trim correction to chase a phantom mixture. Replace the A/F sensor ($180-320 OEM Densi/NTK) only after confirming the upstream causes are clean. The expensive misdiagnosis caveat: don't replace the A/F sensor first — on Infiniti VQ engines, vacuum leaks and dirty MAFs are 70% of P1170 root causes, and a new $300 wideband won't help if the intake is leaking at the manifold gasket.
Vehicle-specific patterns2003-2007 Infiniti G35 (VQ35DE) and 2008-2015 G37/G37x (VQ37VHR) throw P1170 most often from intake-manifold gasket weep or a cracked rubber intake e…
- 2003-2007Infiniti G35 (VQ35DE) and 2008-2015 G37/G37x (VQ37VHR) throw P1170 most often from intake-manifold gasket weep or a cracked rubber intake elbow between the MAF and throttle body — both are common past 80k miles and both create exactly the lean-trim condition that sets P1170.
- 2004-2010Infiniti QX56 with the VK56DE (and 2011-2017 QX56/QX80 with the VK56VD direct-injection version) throws P1170 from intake-gasket failure on the 5.6L V8 and from carbon-fouled GDI intake valves on the VK56VD.
- 2003-2010Infiniti M35/M45 (VQ35DE / VK45DE) shares the VQ35 failure mode on the M35 and shows VK45-specific intake-plenum gasket issues on the M45.
Estimated repair$50 (MAF clean + vacuum-leak repair) to $700 (intake gaskets + A/F sensor + labor).
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