P0319
Rough Road Sensor B Signal CircuitP0319 is a generic OBD-II powertrain diagnostic trouble code: Rough Road Sensor B Signal Circuit. It is logged by the engine control unit when the misfire monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0319 means
P0319 — "Rough Road Sensor \"B\" Signal Circuit" — indicates a PCM-detected electrical fault in the secondary (channel B) rough road sensor circuit. The rough road monitoring system uses one or more sensors to determine whether crankshaft velocity variations are caused by engine misfires or by external road forces acting through the drivetrain. Channel B is the second input channel; its presence depends on the vehicle platform, with some using a two-channel accelerometer arrangement while others derive the signal from dual ABS wheel speed channels via the EBCM.
P0319 is the channel-B counterpart to P0318 (channel A). When the PCM monitors the channel B signal and detects an out-of-range voltage, an open circuit, or a missing signal during a drive cycle, it stores this code. As with P0318, the MIL does not always illuminate — some platforms treat this as a stored-only fault unless it persists across multiple drive cycles. The loss of channel B input may reduce the system's ability to accurately distinguish genuine misfires from road-induced crank irregularities.
Diagnosis follows the same electrical pathway as P0318: inspect connectors and wiring for the channel B circuit, verify supply voltage, measure signal output against spec, and check EBCM health on platforms using ABS-based rough road detection. Addressing connector corrosion or chafed wiring resolves the majority of cases before sensor replacement is needed.
Common causes
Most-frequently reported root causes when P0319 is logged.
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1
Open circuit or broken wire in the rough road sensor \"B\" signal line between the sensor and PCM.
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2
Short to ground or short to battery voltage on the channel B signal circuit.
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3
Corroded, damaged, or unseated electrical connector at the channel B sensor or EBCM.
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4
Failed rough road accelerometer — internal fault on the channel B output stage.
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5
EBCM fault producing invalid or absent data on the channel B rough road input used by the PCM.
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6
Wiring harness damage from heat, chafing, or vibration causing intermittent signal loss on channel B.
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7
PCM input circuit fault specific to the channel B pin.
Symptoms drivers notice
How to diagnose P0319
A typical diagnostic flow when this code is present.
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1
Connect a scan tool and retrieve all stored codes; pay attention to concurrent misfire, ABS, or P0318 codes that may indicate broader sensor system failure.
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2
Inspect the channel B sensor connector and its wiring harness for corrosion, pin damage, or chafing near heat sources or sharp edges.
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3
Measure supply voltage and ground at the channel B sensor connector with the ignition on and compare to manufacturer specifications.
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4
Perform continuity and short-circuit checks on the channel B signal wire using a digital multimeter with the connector unplugged.
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5
Monitor the rough road sensor \"B\" PID on live scan data while driving over varied surfaces to observe signal behavior.
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6
If the platform uses EBCM-sourced rough road data, inspect the EBCM for its own fault codes and verify serial communication health.
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7
Replace the channel B sensor or repair the harness only after electrical tests confirm the fault location; re-run the drive cycle to verify the code does not return.
Related powertrain codes
Frequently asked questions
What is the difference between P0318 and P0319?
Both codes indicate electrical faults in the rough road sensor circuit, but P0318 refers to channel A (the primary sensor input) and P0319 refers to channel B (the secondary input). On two-channel platforms, both channels must be functional for the misfire suppression to work correctly.
Do all vehicles have a channel B rough road sensor?
No. Channel B is only present on platforms that implement a dual-channel rough road detection strategy. Many vehicles use only a single channel or a single accelerometer, so P0319 is less commonly encountered than P0317 or P0318.
Can P0319 cause my car to fail an emissions test?
If P0319 illuminates the MIL, it will cause an emissions test failure in jurisdictions that check for illuminated warning lights. Even if the MIL is off, the compromised rough road monitor can lead to false misfire codes that themselves trigger MIL illumination.
Is P0319 serious enough to stop driving immediately?
Not typically. The code rarely causes immediate driveability problems on smooth roads. However, the misfire monitor may become unreliable on rough surfaces, so the fault should be diagnosed and repaired in a timely manner to avoid masking genuine misfire faults.
Disabling P0319 in software
RaceTune can permanently disable P0319 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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