OBD-II Diagnostic Trouble Code
P0222 — Throttle/Pedal Position Sensor B Circuit Low Input
P0222 means the ECM saw pedal or throttle position sensor B voltage below the minimum expected value. This usually indicates an open signal circuit, a short to ground, or a lost 5V reference. The ECM then relies on sensor A and typically limits power.
Severity 4/5
Truck-relevant
Stop within 50 mi
Severity
Stop within 50 mi
Throttle/Pedal Position Sensor B Circuit Low Input
Code
P0222
Category
Powertrain
Subsystem
Throttle
Truck-relevant
Yes
What this means for truckers
P0222 (Throttle Position Sensor B Low) — secondary TPS on drive-by-wire systems. Failure can disable throttle. Drive-by-wire systems use redundant sensors for safety.
Before you replace parts — try this first
P0222 on the Throttle system is most often open or shorted-to-ground sensor b signal wire — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Check engine light, reduced power or limp mode, engine may only idle, and poor throttle response.
Common causes
- CommonOpen or shorted-to-ground sensor B signal wire ($100–$400)
- CommonFailed accelerator pedal assembly ($150–$500)
- OccasionalLost 5V reference from a short elsewhere on the shared circuit ($150–$500)
- RareECM fault ($1200–$3500)
How to fix
Measure 5V reference and signal voltage at the pedal
When to use: First step
Check signal wire for shorts to ground and continuity to the ECM
When to use: When signal is near 0V
Replace the pedal assembly
When to use: When the reference and wiring are good
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P0200 — Injector Circuit Malfunction
- → P0201 — Injector Circuit Malfunction - Cylinder 1
- → P0202 — Injector Circuit Malfunction - Cylinder 2
- → P0203 — Injector Circuit Malfunction - Cylinder 3
- → P0204 — Injector Circuit Malfunction - Cylinder 4
Frequently Asked Questions
Can I drive with code P0222?
Drive with caution. P0222 is severity 4 — stop within ~50 miles. Most commercial diesel codes at this severity (turbo, fuel rail, transmission solenoid) can damage adjacent expensive components if left unrepaired. Get to a service location before highway-speed loads.
How much does it cost to fix P0222 on a commercial truck?
Total repair cost ranges $100–$3500 depending on the root cause. The cheapest fix is usually the first one listed below — Open or shorted-to-ground sensor B signal wire — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P0222 fail a DOT inspection?
P0222 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P0222 and related codes?
P0222 is closely related to: P0200 (Injector Circuit Malfunction), P0201 (Injector Circuit Malfunction - Cylinder 1), P0202 (Injector Circuit Malfunction - Cylinder 2), P0203 (Injector Circuit Malfunction - Cylinder 3). These codes share the same subsystem (throttle) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P0222 is set without the companions, the issue is more isolated.
How do I prevent P0222 from coming back after a repair?
For P0222 (Throttle/Pedal Position Sensor B Circuit Low Input), prevention centers on the throttle system. Clean throttle body at 100K mile intervals. Don't let carbon build up. Avoid extended idle time.