P24B5 Particulate Matter Sensor Heater Control Circuit Low

P24B5 points to the heater line of the particulate matter sensor being pulled toward ground, so the heater control sees an implausible current while heating is requested. GM's 18OBDG04 table describes it as a ground fault on the heater line and flags it when current is under 0.5 A or above 15 A with the heater commanded on, 30 of 60 samples, Type B with two trips. VW's 2014 Touareg list uses a heater current below 1 A or above 15 A. GM issued PIP5607 for 2019 Silverado and Sierra 2500/3500 with the 6.6L L5P, telling technicians to clear P24B3 or P24B5 because engineering suspected false setting. While the heater cannot work, the sensor cannot clean itself and the filter monitor stops. P24B3 is the open circuit, P24B6 the short to power.

Likely causes

Symptoms

• Malfunction indicator lamp on
• Particulate filter monitor does not complete

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.