What this code means
B2986 can indicate an open in the recirculation control motor circuit.
B2986 concerns an open in the recirculation control motor circuit. The climate control unit monitors the motor's input voltage and stores the code when it is above the specified value. The procedure examines the motor-side circuit output, the two named wire paths and the control unit's internal voltage.
The motor-side and control-unit voltage checks share the same approximate expected value. They remain separate inspections because the probe locations and connector states differ. The resistance checks between them examine the connecting paths.
What the vehicle may do
- Motor input voltage may be higher than the specified value.
Possible fault areas
- The recirculation control motor may have a problem.
- The RFD-P or SENS-COM circuit may have an open wire.
- The climate control unit may have an internal circuit problem.
The output-voltage check is made at the disconnected motor connector with IG Mode ON. The wire checks then examine RFD-P and SENS-COM with the connectors disconnected. The control-unit internal-voltage check uses the connected unit connector in its stated IG condition.
Keeping those connector states visible explains why a normal result at one point cannot replace the result at another point. Each finding leads to the interpretation written for that inspection.
Diagnostic path
Understand the stored condition
B2986 means An Open in the Recirculation Control Motor Circuit. The climate control unit monitors the recirculation control motor's input voltage. If that voltage is higher than the specified value, the unit stores this code. Possible fault areas include the motor, its related wiring, and the climate control unit.
Check the motor circuit output voltage
This check evaluates the component through its related components. Turn the vehicle to the ON mode. Disconnect the recirculation control motor connector (5P). Keep IG Mode ON for the unit output voltage check. At the disconnected connector, place one probe on female terminal 3.
- Other probe: female terminal 4.
- Normal reading: about 5 volts.
If the reading is normal, this check points to a problem with the motor. If the reading is abnormal, it points to a problem with other related components.
The motor-side reading uses female terminals 3 and 4 of the disconnected 5P connector. The internal-voltage check later uses terminals 17 and 19 of the connected climate control unit connector B (24P). Both use about 5 volts as the normal criterion, but the setups describe different points in the circuit.
The wire measurements connect those points: RFD-P uses motor terminal 4 and unit terminal 17, while SENS-COM uses motor terminal 3 and unit terminal 19. The wire criterion is less than 1 ohm with the specified disconnections. These endpoint relationships make the sequence understandable without changing any of its measurement conditions.
Check the RFD-P wire
Check wires RFD-P and SENS-COM for an open wire. Keep the recirculation control motor connector (5P) disconnected. Disconnect climate control unit connector B (24P) as well. Use IG Mode OFF for the resistance check.
- First probe: female terminal 4 at the disconnected recirculation control motor connector (5P).
- Other probe: female terminal 17 at the disconnected climate control unit connector B (24P).
- Normal reading: less than 1 ohm.
An abnormal result means there is a problem in the circuit.
Check the SENS-COM wire
Keep IG Mode OFF and both connectors disconnected. Check the SENS-COM wire next.
- First probe: female terminal 3 at the disconnected recirculation control motor connector (5P).
- Other probe: female terminal 19 at the disconnected climate control unit connector B (24P).
- Normal reading: less than 1 ohm.
An abnormal result means there is a problem in the circuit.
Check the climate control unit
Keep the recirculation control motor connector (5P) disconnected. Make sure climate control unit connector B (24P) is connected for this check. Use IG Mode ON to check the unit's internal circuit voltage. At the connected climate control unit connector B (24P), place one probe on female terminal 17.
- Other probe: female terminal 19.
- Normal reading: about 5 volts.
An abnormal reading means there is a problem with the climate control unit.
Takeaway
These checks help you narrow down B2986 using motor-circuit voltage, wire resistance, and the climate control unit's internal voltage.
Final check
Voltage and resistance checks can help narrow the fault to the motor, related wiring, or climate control unit.
Read the final fault area from the appropriate inspection result. The output-voltage check, the individual wire readings and the climate-control-unit check answer different questions within the same circuit diagnosis.
