P0123

High Severity

Throttle Position Sensor A Circuit High

Fuel System

What Does P0123 Mean?

TPS voltage is above maximum expected. ECM sees the throttle as more open than it actually is.

Common Fix

Replace TPS

Estimated Cost (DIY)

$20 - $100

Symptoms

  • ⚠️High idle
  • ⚠️Surging
  • ⚠️Hesitation
  • ⚠️Reduced power mode

Common Causes

Failed TPSlikely
Open ground wirepossible
Short to voltage in signal wirepossible

How to Diagnose P0123

  1. 1Measure TPS voltage — should be ~0.5V at closed throttle
  2. 2Check TPS connector and ground wire
  3. 3Inspect for shorts in wiring
  4. 4Replace TPS

OEM Diagnostic Flowchart

Scroll to load technician if/then branches.

Read live data and freeze frame for P0123 to pinpoint the cause before buying parts.

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Related Resources

Repair guides, symptom pages, and wiring diagrams related to P0123.

OEM Manual Evidence

Browse →
2013 GMC Truck Yukon XL Denali AWD V8-6.2L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...

2013 GMC Truck Yukon XL Denali 2WD V8-6.2L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...

2013 GMC Truck Yukon XL 4WD V8-6.0L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-6.0L Service Manual | Operation CHARM Operation CHARM : Car repair...

2013 GMC Truck Yukon XL 4WD V8-5.3L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...

Exact Vehicle Hubs

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2013 Gmc Truck Yukon Xl 4wd V8 5.3l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0123.

2013 Gmc Truck Yukon Xl 4wd V8 6.0l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0123.

2013 Gmc Truck Yukon Xl Denali 2wd V8 6.2l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0123.

2013 Gmc Truck Yukon Xl Denali Awd V8 6.2l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0123.

Related Codes

P0120: Throttle Position Sensor A CircuitRelated

General fault in the TPS circuit. The TPS tells the ECM how far the throttle is open.

P0121: Throttle Position Sensor A Range/PerformanceRelated

The TPS reading does not match expected values based on MAP, RPM, and other inputs. Erratic readings indicate a worn TPS.

P0122: Throttle Position Sensor A Circuit LowRelated

TPS voltage is below minimum threshold. The ECM cannot determine throttle position accurately.

Frequently Asked Questions

What causes TPS high voltage?
Usually a failed TPS or an open ground wire that pulls the signal high. Less commonly a short in the wiring.
Does P0123 cause high idle?
Yes — the ECM thinks the throttle is partly open and may raise idle speed or behave erratically.

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