Code
P1158
CITROEN
P — Powertrain
Electric throttle signal malfunction
Views:
UK: 3
EN: 5
RU: 3
AI status
Completed
Completed
100%
Causes
- Faulty throttle position sensor(s) or accelerator pedal position sensor(s)
- Open/short or poor connection in wiring harness or connector to throttle body/accelerator pedal
- Faulty electronic throttle body (motor, gearbox or internal sensor)
- Poor battery voltage, weak battery or bad ground connection
- Contaminated or mechanically binding throttle plate (carbon build-up)
- Missing or failed fuse/relay for throttle control
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power / limp home mode
- Erratic or high/low idle, stalling at idle
- Poor or delayed throttle response, hesitation
- Inability to accelerate normally
- Throttle pedal may feel normal while vehicle does not respond
What to check
- Read freeze frame and live data with a scan tool; note throttle position, pedal position, battery voltage and fault history
- Inspect connectors and wiring at throttle body and accelerator pedal for corrosion, damage, water intrusion or loose pins
- Check fuses and relays related to throttle/ECU power and control
- Measure reference voltage (usually 5 V) and ground at sensor connector
- Measure TPS/APP sensor output voltage at closed and open positions and compare to expected values
- Perform wiggle test on wiring while watching live data for intermittent changes
Signal parameters
- Reference voltage to sensors: ~5.0 V (typically 4.75–5.25 V)
- Throttle / pedal sensor output: typically ~0.5–4.5 V across range (idle ≈ 0.5–1.0 V, wide open ≈ 4.0–4.5 V)
- Dual-sensor correlation: two channel signals should track closely; difference usually
- Throttle actuator drive: controlled by ECU (PWM or DC drive); PWM frequency often tens to a few hundred Hz depending on system
- Expected continuity: low resistance to ground/5V reference circuits; no open circuits
Diagnostic algorithm
- Connect a capable scan tool, record freeze frame and live data (throttle position, pedal position, battery voltage, related PIDs).
- Verify battery voltage is healthy (>12 V with engine off; >13.5 V charging) and check engine grounds.
- Visually inspect connectors and wiring harness at the throttle body and accelerator pedal for damage, corrosion, or moisture. Repair as needed.
- With ignition on, measure reference 5 V and ground at the sensor connector. If absent or out of range, trace power/ground/fuse/relay.
- Measure TPS/APP voltages at connector during closed and open positions; compare to signal parameter ranges and check dual-sensor agreement.
- Perform a wiggle / backprobe test on wiring while monitoring live data to detect intermittent faults.
- Command throttle actuator (if supported by scan tool) to verify motor movement and observe current/response. Listen for unusual noises.
- Remove and inspect throttle body for carbon build-up or mechanical binding; clean if required and re-test.
- If wiring, connectors and sensors test OK, consider replacement of the throttle body or pedal sensor as per test results.
- After repair or replacement, perform throttle adaptation/learn procedure per manufacturer instructions, clear codes and road test to confirm repair.
Likely causes
- Corroded or loose connector at the throttle body or pedal sensor
- Intermittent wiring (chafing, broken wire, water ingress) between sensor/actuator and ECU
- Defective throttle position sensor or dual-sensor disagreement
- Throttle motor or drive circuit fault in the throttle body
- Low reference voltage (5V) or poor ground
Fault status
Status
P1158 — Electric throttle signal malfunction. Throttle/accelerator sensor or actuator circuit is reporting implausible or missing signals. Check wiring, connectors, sensor outputs, throttle actuator and perform adaptation after repairs.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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