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P0222 = sensor B voltage stuck low. Either the signal wire has shorted to ground, the 5V reference is missing, or the sensor itself is dead. Backprobe the connector with a multimeter - B-signal at idle should typically be ~0.5V, climbing smoothly with throttle. See multimeters on Amazon ↑
🗺️ Where Is the Problem?
Blueprint view - P0222 secondary throttle/pedal sensor (B) signal stuck low
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0222 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
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🎯 Top Causes & Probability
60%
#1 - Most Likely
Failed B Sensor in Throttle Body or Pedal
The B-sensor element has failed open or shorted internally and reads at or near 0V. Replacement of the throttle body (or pedal module) almost always clears it. This is the most common cause on drive-by-wire vehicles past 100k miles.
🔩 Part
$120–$400
👨🔧 Labor
$80–$160
⚡ DIY Difficulty
Easy
30%
#2 - Check First
Signal Wire Shorted to Ground
A chafed B-signal wire grounding against the chassis or engine drops voltage to 0V. Inspect the harness for rub-through, especially near the throttle body bracket and along firewall pass-throughs.
🔩 Part
$10–$60
👨🔧 Labor
$80–$200
⚡ DIY Difficulty
Medium
10%
#3 - Less Common
Loss of 5V Reference Voltage
If the 5V reference from the PCM to the sensor is missing (open wire or PCM driver failure), sensor B reads zero. Verify with a meter at the connector. Repair the open or, rarely, replace the PCM.
🔩 Part
$20–$120
👨🔧 Labor
$120–$300
⚡ DIY Difficulty
Medium
🚗 Most Affected Vehicles
🔧 Step-by-Step Diagnosis
- Read live data on TPS/APP B - With the key on, observe sensor B voltage. P0222 sets when voltage stays at or below ~0.2V at idle. If it never rises with throttle, the signal is stuck low.
- Check 5V reference and signal wire - At the throttle body or pedal connector, backprobe to verify ~5V on the reference pin. With key on and pedal varied, signal pin should sweep smoothly. 0V signal with good 5V reference points to a shorted/failed sensor.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need