A short to ground in the signal wire between the EGR throttle control circuit B and the powertrain control module; A faulty EGR throttle position sensor or actuator assembly internal to the throttle body; Corroded, loose, or damaged electrical connector pins at the EGR throttle body or PCM; A failed powertrain control module driver for that specific circuit, though this is less common; Aftermarket or improperly installed electrical accessories tapping into the circuit and pulling voltage low; Water intrusion into the connector or throttle body causing intermittent low-voltage signals

DTC codes / P21xx · Fuel and air metering / P213C

P213CEGR Throttle Control Circuit B Low

Q: What does code P213C mean?

EGR Throttle Control Circuit B Low. P213C indicates that the powertrain control module has detected a low-voltage condition on the signal circuit for the EGR throttle control circuit B, which is the second throttle plate used to regulate exhaust gas recirculation flow. The computer expects a certain voltage range on this circuit and sees it persistently below the acceptable threshold, so it flags the circuit as low.

P213C indicates that the powertrain control module has detected a low-voltage condition on the signal circuit for the EGR throttle control circuit B, which is the second throttle plate used to regulate exhaust gas recirculation flow. The computer expects a certain voltage range on this circuit and sees it persistently below the acceptable threshold, so it flags the circuit as low.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or stumbling when the engine is cold or under light load
Hesitation or a slight surge during acceleration as the EGR throttle fails to modulate
Increased exhaust emissions that may cause a state inspection failure
In some cases, a limp-home mode with reduced engine power
A faint electrical burning smell or visible chafed wiring near the EGR throttle body

Common causes, most likely first

A short to ground in the signal wire between the EGR throttle control circuit B and the powertrain control module
A faulty EGR throttle position sensor or actuator assembly internal to the throttle body
Corroded, loose, or damaged electrical connector pins at the EGR throttle body or PCM
A failed powertrain control module driver for that specific circuit, though this is less common
Aftermarket or improperly installed electrical accessories tapping into the circuit and pulling voltage low
Water intrusion into the connector or throttle body causing intermittent low-voltage signals

How to diagnose and fix it

Use a scan tool to verify P213C is current and check for any related pending codes or freeze-frame data
Visually inspect the EGR throttle body connector and wiring for chafing, corrosion, or loose pins
Disconnect the EGR throttle body and measure resistance from the signal circuit B terminal to ground to check for a short
Back-probe the signal circuit at the PCM connector and compare voltage with the throttle body connected and disconnected
If wiring and connectors are good, substitute a known-good EGR throttle body and clear codes to see if the fault returns
Check for technical service bulletins or software updates for the PCM that address false low-voltage reporting
After repair, clear codes and perform a drive cycle that includes EGR activation to confirm the fix

What the low-voltage code really means

A low-voltage code on a throttle control circuit often comes from a poor ground or a shorted signal wire rather than a failed throttle body, so always check the harness before replacing parts.
The EGR throttle control circuit B is sometimes shared with other sensors on the same 5-volt reference, and a fault in one can drag down the voltage seen by the PCM and set this code.
Intermittent low-voltage faults frequently occur only when the engine is hot or vibrating, so a wiggle test of the harness while monitoring live data is more reliable than a static meter check.
Some vehicles use the EGR throttle for both emissions control and intake air regulation, so a failing circuit can cause drivability symptoms that seem unrelated to the EGR system.
A generic P213C does not tell you which specific wire or component is at fault, and misdiagnosis often leads to unnecessary replacement of the EGR throttle body when the real issue is a chafed wire near the exhaust manifold.

Can I keep driving with P213C?

You can usually drive the vehicle with P213C set, but avoid heavy acceleration and long uphill grades because the EGR throttle may not regulate properly and could cause poor engine performance or increased emissions. If the check engine light flashes or you notice severe power loss, stop driving and have the fault diagnosed promptly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.