P2D23: Turbocharger Interstage Pressure Sensor A Circuit Low

What it means

The ECM detects a circuit low fault on the turbocharger interstage pressure sensor a circuit. Reading cannot be used reliably for control.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

Turbocharger interstage pressure Sensor A reports pressure between turbocharger stages to the ECM for boost control. P2D23 sets when the Sensor A signal circuit voltage is lower than the ECM's expected range, which can result from a grounded signal wire, a shorted sensor, or a poor connection.

Common causes

Most likely first.

1. Signal wire shorted to ground
2. Internal sensor short
3. Connector pins corroded - high contact resistance

Symptoms

• Check engine light on
• Significant power loss / limp mode
• Possible blue or black smoke from exhaust
• Whistling or hissing sound from intake

How to diagnose it

1. Review freeze-frame data and Sensor A live data; a reading pinned low when pressure should change helps confirm the circuit-low condition.
2. Inspect Sensor A's connector and harness for rubbed-through insulation, pinched sections, corrosion, or fluid intrusion that could pull the signal low.
3. Check that Sensor A's connector terminals are firmly seated and that the sensor ground and supply connections are intact.
4. With the wiring diagram, test the Sensor A signal circuit for a short to ground and check supply and ground circuits against the manufacturer's specification.
5. If the wiring is sound, test Sensor A's output and replace it only if it is internally shorted or outside the manufacturer's specification.

Common fixes

• Repair a Sensor A signal wire shorted to ground.
• Clean or repair corroded Sensor A connector terminals.
• Replace Sensor A if testing confirms an internal short.
• Clear the code and verify the signal changes with operating conditions.

Can I keep driving?

Limit driving to necessary trips if power is reduced, and avoid towing or hard acceleration because boost control may be impaired. Stop if the engine loses substantial power or produces heavy smoke.