Engine-Codes - Ford - P0161 2003 FORD F150

P0161 2003 FORD F150 Code - O2 Sensor Heater Circuit Bank 2 Sensor 2

- Code Popularity: 4,945 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
Table of contents

|What are the Possible Causes of the P0161 2003 FORD F150 Code?

  • Faulty Rear Heated Oxygen Sensor Bank 2
  • Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
  • Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
  • Inappropriate fuel pressure
  • Faulty fuel injectors
  • Intake air leaks
  • Exhaust gas leaks

|How to Fix the P0161 2003 FORD F150 Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|P0161 2003 FORD F150 code tech notes

Replacing the Rear Heated Oxygen Sensor Bank 2 usually takes care of the problem.
During testing the HO2S Heaters are checked for opens/shorts and excessive current draw. The test fails when current draw exceeds a calibrated limit and/or an open or short is detected.

|What is the cost to diagnose the P0161 2003 FORD F150 code?

Labor: 1.0

The cost to diagnose the P0161 2003 FORD F150 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

|When is the P0161 2003 FORD F150 code detected?

Current amperage in the rear heated oxygen sensor heater circuit is out of the normal range.

|What are P0161 2003 FORD F150 code possible symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Possible higher than usual fuel consumption

|What Does the P0161 2003 FORD F150 Code Mean?

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

O2 Sensor Heater Circuit Bank 2 Sensor 2

|Need more information with the P0161 2003 FORD F150 code?

Need more information on how to fix the P0161 2003 FORD F150 code?
Get Access to Factory Service Manuals

|Need help with a P0161 2003 FORD F150 code?

Get the P0161 2003 Ford F150 code diagnosed by a professional: Find a repair shop in your area