Code
P1706
FIAT
P — Powertrain
Throttle signal fault
AI status
Completed
Completed
100%
Causes
- Damaged or corroded connector or wiring between throttle body / accelerator pedal and ECU
- Faulty throttle position sensor (TPS) or accelerator pedal position (APP) sensor
- Contaminated or mechanically binding throttle body
- Poor power or ground to sensor circuits
- Intermittent short to battery or ground, or high resistance in the circuit
- Faulty engine control module (ECU) or internal software fault
Symptoms
- Check Engine Lamp (MIL) illuminated
- Reduced engine power or vehicle in limp/home mode
- Poor or delayed throttle response, hesitation
- Unstable or high/low idle
- Stalling at idle or during acceleration
- Possible inability to restart in some cases
What to check
- Read freeze frame and full DTC list with a capable scan tool; note conditions when code set
- View live data: TPS and APP voltages/percentages and correlation between redundant sensors
- Verify vehicle battery voltage and charging system under load
- Visually inspect connectors and wiring for damage, corrosion, or water ingress
- Backprobe sensor connectors and measure supply (reference voltage), signal, and ground
- Wiggle test harness and connectors while monitoring live data for intermittent faults
Signal parameters
- Typical sensor reference voltage: ~5.0 V (varies by model) — check OEM spec
- Expected idle signal voltages: approx. 0.5–1.0 V (first sensor) and complementary value on second sensor; full throttle ~4.0–4.5 V
- Valid operating range: ~0.2 V to ~4.9 V — values outside this range indicate open/short
- Redundant sensor correlation: sensors should track each other; difference >0.5 V or inverse correlation fault triggers errors
- Signal update: steady analog or PWM waveform without dropouts — intermittent or noisy signals indicate wiring or grounding issues
Diagnostic algorithm
- Connect scan tool, record freeze frame and note whether code is current or historic.
- With ignition ON (engine OFF), monitor APP (pedal) and TPS (throttle body) live data while pressing pedal and manually moving throttle; check that both sensors move smoothly and correlate.
- Measure reference voltage (usually ~5 V), signal voltage at rest and at full travel, and ground continuity at sensor connector. Compare to OEM specs.
- Inspect and repair any damaged wiring, pins, or connectors. Clean contacts and apply dielectric grease if appropriate.
- Perform a wiggle test of harness while monitoring live signals to find intermittent faults.
- Remove and inspect throttle body for carbon build-up or mechanical binding; clean or service as required.
- If sensor voltages or correlation are out of spec, replace the faulty sensor (APP or TPS/throttle body) and retest.
- After repairs, clear codes, perform any required throttle / idle relearn or ECU adaptation procedure, then road test to confirm no return of the fault.
- If wiring and sensors check OK and fault persists, consider ECU or gateway module diagnosis with manufacturer-level tools.
Likely causes
- Wiring harness chafed or pinched near engine or firewall
- Corroded / loose connector pin at throttle body or pedal module
- TPS/APP sensor failed or out of specification
- Throttle body carbon build-up preventing proper movement or sensing
- Blown sensor supply fuse or poor ground at chassis/engine block
- Failed throttle actuator or internal potentiometer in throttle body
Fault status
Status
Throttle signal fault — inconsistent or out-of-range throttle/pedal sensor signal. May cause reduced power (limp mode).
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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Repair manuals
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26
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