P1170 – OBD-II DTC

OBD-II DTC P1170 – Lack Of HO2S22 Switch – Sensor Indicates Rich

DTC P1170 meaning

DTC P1170 refers to a diagnostic trouble code indicating a lack of response from the heated oxygen sensor (HO2S) 2, specifically sensor 2, which is indicating a rich fuel mixture. This code is part of the OBD-II system and is triggered when the engine control module (ECM) detects that the HO2S 2 is not switching as expected, suggesting that the exhaust gases are too rich in fuel.

DTC P1170 symptoms

Common symptoms associated with DTC P1170 may include:

• Check Engine Light illuminated
• Decreased fuel efficiency
• Rough engine idle
• Increased emissions
• Possible engine stalling

DTC P1170 causes

Several factors can lead to the triggering of DTC P1170, including:

• Faulty heated oxygen sensor (HO2S) 2
• Wiring issues or poor connections in the sensor circuit
• Exhaust leaks before the sensor
• Fuel system problems, such as a malfunctioning fuel injector
• Engine control module (ECM) issues

DTC P1170 seriousness

DTC P1170 is considered a moderate to serious issue. While it may not cause immediate engine failure, it can lead to:

• Increased fuel consumption
• Higher emissions, potentially failing emissions tests
• Long-term engine damage if not addressed

How to diagnose DTC P1170

To diagnose DTC P1170, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1170 code.
2. Inspect the HO2S 2 wiring and connectors for damage or corrosion.
3. Check for exhaust leaks before the sensor.
4. Test the HO2S 2 with a multimeter to ensure it is functioning correctly.
5. Examine the fuel system for issues, such as clogged injectors or a faulty fuel pressure regulator.
6. Review the ECM for any software updates or faults.

How to fix DTC P1170 step-by-step instructions

To fix DTC P1170, follow these steps:

1. Repair or replace any damaged wiring or connectors related to the HO2S 2.
2. Fix any exhaust leaks found during diagnosis.
3. If the HO2S 2 is faulty, replace it with a new sensor.
4. Address any fuel system issues, such as cleaning or replacing fuel injectors.
5. Clear the DTC using an OBD-II scanner and perform a test drive to ensure the code does not return.

How to erase DTC P1170

To erase DTC P1170, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the engine to verify that the code does not return.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.