Tracking Down P0122 on Your 2017 Honda Accord
A P0122 on your 2017 Honda Accord indicates the ECM has caught the throttle position sensor voltage dropping below the minimum threshold. At 7–9 years old, this circuit fault is typically caused by age-related electrical degradation. Our detective is focused on the physical connections and wiring rather than software or calibration.
The 2017 Accord (9th generation, final year) uses a 2.4L i-VTEC four-cylinder (185 hp) or 3.5L V6 (278 hp), both with port injection and electronic throttle control. The port-injection engines are less prone to carbon issues, but P0122 is an electrical problem that affects all engine types equally.
Symptoms
- Check engine light on
- Severe throttle response loss
- Engine may not respond to accelerator
- Harsh limp mode
- Stalling risk, especially during deceleration
Causes at This Age
- Connector terminal corrosion – Years of heat cycling, road salt, and moisture. Likelihood: 40%
- Throttle body assembly failure – Internal TPS sensor wear and degradation. Likelihood: 30%
- Wiring harness damage – Aged insulation, chafing, possible rodent damage. Likelihood: 15%
- 5V reference fault – Shared reference line problem. Likelihood: 10%
- Ground circuit issue – Corroded ground connections. Likelihood: 5%
Repair Costs
- Connector cleaning/repair: $50–$150
- Throttle body replacement: $250–$450 parts and labor
- Wiring repair: $150–$300
- Ground repair: $30–$100
DIY Feasibility: High
All warranties are expired or expiring on a 2017 Accord. The federal emissions warranty (8 years/80,000 miles) expires in 2025. This is a strong DIY candidate. The throttle body is easily accessible on both the 2.4L and 3.5L engines. Start with connector inspection and cleaning. If the TPS still reads below 0.2V with a good connector and 5V reference present, replace the throttle body. Parts: $80–$180 online. After replacement, idle relearn: key ON 10 seconds, start, idle 10 minutes.
How AutoDetective AI Can Help
AutoDetective's AI guides you through the diagnostic process for P0122. Upload your scan data for a free step-by-step diagnosis.