Investigating P0122 on Your 2016 Honda Civic
A P0122 on your 2016 Honda Civic signals that the throttle position sensor voltage has dropped below the minimum acceptable level. This is a circuit-level failure—the TPS signal has gone critically low, indicating a broken communication path rather than just noisy data. At 8–10 years old, age-related electrical degradation is the primary suspect.
The 2016 Civic was the first year of the 10th generation, available with a 2.0L NA four-cylinder or 1.5L VTEC turbo. The electronic throttle body with integrated TPS has been through years of heat cycling, vibration, and environmental exposure.
Symptoms
- Check engine light on
- Severe throttle response loss or failure
- Engine idles but won't accelerate
- Limp mode with limited power
- Possible stalling
Causes at 8+ Years
- Connector corrosion and terminal damage – Years of heat and moisture exposure. The most common cause at this age. Likelihood: 35%
- Failed throttle body assembly – Internal TPS sensor worn out after years of service. Likelihood: 30%
- Wiring harness damage – Aged insulation, chafing, rodent damage. Likelihood: 20%
- 5V reference circuit issue – Another sensor pulling the shared reference low. Likelihood: 10%
- Ground deterioration – Corroded engine/body grounds. Likelihood: 5%
Repair Costs
- Connector cleaning/repair: $50–$150
- Throttle body replacement: $220–$420 parts and labor
- Wiring repair: $150–$300
- Ground strap repair: $30–$100
DIY Feasibility: High
All warranties have expired on a 2016 Civic, including the federal emissions warranty (8 years expired in 2024). This is a good DIY candidate. Start by inspecting and cleaning the throttle body connector. Check for 5V reference voltage with a multimeter. If the connector and wiring check out, replace the throttle body—parts run $100–$200 online, and installation takes about an hour. After replacement, perform Honda's idle relearn: key ON 10 seconds, start the engine, idle 10 minutes.
How AutoDetective AI Can Help
AutoDetective's AI helps pinpoint whether your P0122 is a simple connector fix or requires throttle body replacement. Upload your scan data for free.