Code
C1222
HYUNDAI
C — Chassis
Throttle Position Sensor(TPS) - High Input
Views:
UK: 16
EN: 17
RU: 28
AI status
Completed
Completed
100%
Causes
- Faulty throttle position sensor (TPS)
- Short to battery voltage on the TPS signal wire
- Poor or corroded connector or pin (TPS harness)
- Open or high-resistance sensor ground or reference circuit
- Damaged wiring (chafing, pinched, water intrusion)
- Faulty engine control module (ECM) or internal TPS circuit fault
Symptoms
- Check Engine / MIL illuminated
- Reduced engine power or limp-home mode
- Poor or delayed throttle response, hesitation
- Engine idle problems (high/unstable idle or stalling)
- Possible lack of acceleration or surging
What to check
- Retrieve freeze frame and live data with a scan tool (TPS voltage/percentage)
- Visual inspection of TPS connector and wiring for damage or corrosion
- Backprobe TPS connector to verify reference voltage (typically 5 V) and ground
- Measure TPS signal voltage at closed and open throttle positions
- Wiggle harness while monitoring live data to find intermittent faults
- Check for related codes (engine or throttle actuator codes)
Signal parameters
- Reference voltage: ~5.0 V (check OEM spec)
- Signal voltage (typical): ~0.2–1.0 V at closed throttle, ~4.0–4.9 V at wide-open throttle
- Signal should rise smoothly with throttle movement (no sudden jumps or dropouts)
- Minimum/maximum thresholds vary by model — consult Hyundai wiring diagrams/specs if available
Diagnostic algorithm
- Record freeze frame, retrieve all stored codes and note conditions when C1222 set.
- Visually inspect throttle body connector and wiring for damage, corrosion, or water ingress. Repair connector issues as found.
- With key ON (engine OFF) backprobe the TPS connector: verify 5 V reference present, good ground, and measure signal voltage. Compare to expected closed-throttle voltage.
- Slowly open throttle while monitoring TPS signal with a scan tool or DVOM/oscilloscope. Confirm signal rises smoothly from closed to open without spikes or dropouts.
- If signal is stuck high or shows short to voltage, isolate by disconnecting TPS. Verify signal line at ECM harness pin (or measure for short to 12 V).
- Perform continuity/resistance checks of harness between TPS and ECM; repair any short/open/high resistance conditions.
- If wiring and connector are good but TPS output is out of spec, replace the TPS/throttle body assembly per Hyundai procedures.
- If replacement does not clear code, test/verify ECM power/grounds and consult manufacturer procedures for ECM diagnosis or reprogramming.
- After repairs, clear codes and perform road/drive cycle to verify the fault does not return.
Likely causes
- Faulty TPS (most common)
- Shorted signal wire to 5V/12V supply
- Corroded/loose connector at the throttle body
- Poor ground or reference voltage at ECM
- Intermittent wiring fault from harness damage
Fault status
Status
Throttle Position Sensor circuit is reporting a high voltage/signal input to the ECM.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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