B2105

Code

Other B — Body

Throttle Position Input Out of Range Low

Brand: Other

Type: B — Body

Views: UK: 26 EN: 40 RU: 32

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Page language: EN

Causes

Open or shorted TPS signal wire (short to ground)
Low or missing 5 V reference to the TPS
Poor ground at the TPS or ECU
Failed throttle position sensor
Corroded/loose connector or bent pins
Faulty throttle body or mechanical binding of throttle plate

Symptoms

Engine may enter limp-home or reduced-power mode
Hard or unpredictable throttle response; hesitation or stalling at idle
Check Engine Light / MIL illuminated and stored B2105 (and possibly related powertrain codes)
Inconsistent idle speed or surging
Inability to accelerate properly

What to check

Read and record freeze-frame and pending/related DTCs with a scan tool
Visually inspect TPS connector and wiring for damage, corrosion, pin push-out or contamination
Check for aftermarket modifications near the throttle body or wiring harness
Confirm no mechanical obstruction or binding of the throttle plate
Perform a key-on (engine off) data-list check of TPS voltage/position and 5 V reference using a scan tool

Signal parameters

TPS is a 3-wire sensor: 5 V reference, ground, and signal (typical vehicles)
Nominal signal range: approximately 0–5.0 V proportional to throttle position (closed/throttle-off near the low end)
Low-range fault means signal is below the expected minimum for closed/throttle-off (near 0 V or lower than manufacturer threshold)
Exact voltages and thresholds vary by manufacturer — consult vehicle service data

Diagnostic algorithm

Retrieve DTCs and live data (TPS voltage/position, throttle actuator status, reference voltage, sensor ground). Note freeze frame.
Inspect harness and connector at the TPS and along the wiring for chafing, pin corrosion, or water intrusion. Repair any visible damage.
With ignition ON (engine off), measure TPS signal wire voltage at the connector using a DMM: verify 5 V reference present, good ground, and signal voltage. Compare to manufacturer spec. Do not crank while measuring reference unless specified.
If reference or ground is missing or low, trace and repair wiring to the ECU (repair corroded grounds, restore 5 V supply).
If reference and ground are correct but signal is low, unplug the sensor and check for short to ground on the signal circuit (ohmmeter or back-probe with harness disconnected).
Wiggle test the harness while monitoring signal to reproduce intermittent faults. Inspect for pin push-out or loose terminals.
If wiring checks good, replace the throttle position sensor or throttle body assembly per service manual and re-test.
After repairs clear codes, perform throttle adaptation/calibration if required by the manufacturer, then verify repair by road test and re-scan for codes.
If issue persists after replacing sensor and repairing wiring, suspect ECU input circuit fault and consider ECU testing or replacement per manufacturer guidance.

Likely causes

Damaged/shorted TPS signal wire or connector causing low voltage
Failed throttle position sensor
Poor ground or low 5 V reference at the sensor

Fault status

⚠️ Status

Throttle Position Input Out of Range Low — TPS signal voltage is below the expected minimum. Possible causes include short to ground, failed sensor, bad reference/ground, or wiring/connector faults.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5–3.0 hours