2010 Mazda B Series OBD2 Code B1948 Climate Control Water Temperature Sensor Circuit Short To Ground

B1948 code definition

The B1948 code is a manufacturer-specific body code related to the climate control system. In this case, the engine control module (ECM) has detected a fault or a short to ground in the circuit for the climate control water temperature sensor.

What the B1948 code means

A code B1948 will be stored when the ECM detects a coolant temperature signal circuit fault between the instrument pack and the air conditioning / climate control module (A/CCM). The A/CCM receives an engine coolant temperature voltage signal from the instrument pack.

The A/CCM monitors the engine coolant temperature circuit for open circuit, high resistance and short circuit conditions. If a fault is present, a DTC will be flagged. If a circuit fault occurs between the coolant temperature sensor and the instrument pack, the instrument pack output will default to a voltage equal to 68-degrees Fahrenheit. If a circuit fault occurs between the instrument pack and the A/CCM, the A/CCM will substitute a default value of 169-degrees Fahrenheit.

What causes the B1948 code?

Several problems may cause a B1948 code including:

• Damaged or defective wiring and related electrical components
• Signal circuit between instrument pack and A/CCM short circuit to ground
• Harness/wiring problems between heater valve and climate control module
• Fault or failure at one (or more) of the air mixing/blending flaps
• Fault in the pressurized A/C system , including condenser fan, compressor, refrigerant pressures/leaks
• Damaged or defective heater fan
• Damaged or defective climate control module

What are the symptoms of the B1948 code?

Symptoms of a B1948 code may include: * Check engine or warning light may illuminate * The air condition/climate control system may not function correctly (for example, blowing warm air only)

How does a mechanic diagnose the B1948 code?

A mechanic may use several methods to diagnose a B1948 trouble code, including: * Utilize an OBD-II scanner to check for a stored B1948 trouble code * Visually inspect wiring and related electrical components for damage or defects * Visually inspect for any leaks in the A/CCM system * Check operation of pressured air conditioning system * Check the fuse for the heater valve to see if blown or damaged * Check the connection to the heater valve for damage or loose connectors or corrosion on the valve itself * Check the evaporator discharge temperature sensor(s) for damage or defect * Test the voltage, current, and resistance on the heater valve

How serious is the B1948 code?

Because a 2010 Mazda B Series 's safe driving operation will not be impacted due to faults that store a B1948 code, this code is not considered a serious code. When this code appears, it is recommended to take your 2010 Mazda B Series to your local service center or mechanic for repair and diagnosis as soon as possible.

What repairs can fix the B1948 code?

Several repairs can fix a B1948 trouble code and include:

• Repair or replace any damaged, corroded, open, or shorted wiring and related electrical components
• Repair any possible leaks in the A/CCM system
• Replace damaged, defective, or blown fuses
• Replace damaged or defective heater valve
• Replace damaged or defective evaporator discharge sensor
• Clear all codes, test-drive your 2010 Mazda B Series , and rescan to see if any codes reappear

Need help with a B1948 code?