What Does B1968 Mean?
This code indicates the body control module (BCM) has detected a fault in the A/C water pump detection circuit. The system is unable to detect proper operation or feedback signal from the water pump that circulates coolant through the A/C evaporator or cabin heating system. This suggests an open circuit, short circuit, or failed water pump motor that prevents the BCM from confirming pump operation.
Common Causes
35%
Failed A/C water pump motor or internal pump circuit failure
30%
Damaged wiring harness or corroded connector at water pump
20%
Faulty BCM relay or internal BCM driver circuit failure
10%
Blown fuse or fusible link in water pump power circuit
5%
Water pump seized due to coolant contamination or debris
Diagnostic Steps
1
Step 1: Visually inspect the A/C water pump location (typically near firewall or under dash) for coolant leaks, damaged wiring, or corroded connectors. Check the water pump fuse in the fuse box and verify continuity with a multimeter.
2
Step 2: Disconnect the water pump electrical connector and use a multimeter to measure voltage at the harness side connector while commanding pump activation through the scan tool. Should see battery voltage (12-14V) when activated.
3
Step 3: Measure resistance across the water pump motor terminals (pump side of connector). Typical readings should be 1-5 ohms depending on manufacturer. Infinite resistance indicates open motor winding, near-zero indicates shorted winding.
4
Step 4: Apply direct 12V power to the water pump motor terminals using jumper wires and battery to verify mechanical operation. Listen for motor operation and check for coolant flow. If pump runs, suspect wiring or BCM issue; if no operation, replace pump.
5
Step 5: Inspect wiring harness for shorts to ground or open circuits by checking continuity between BCM connector and pump connector terminals with harness disconnected at both ends. Repair or replace harness as needed.
6
Step 6: Clear codes, reconnect all components, and test system operation through scan tool active tests. Monitor live data for pump feedback signal and verify proper operation through complete heating/cooling cycle.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the body control module (BCM) has detected a fault in the A/C water pump detection circuit. The system is unable to detect proper operation or feedback signal from the water pump that circulates coolant through the A/C evaporator or cabin heating system. This suggests an open cir...
The most common cause of B1968 (A/C Water Pump Detection Circuit Failure) is: Failed A/C water pump motor or internal pump circuit failure
Typical repair costs for B1968 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this affects cabin climate comfort only. The A/C and heating system may not function properly, causing reduced defrost capability which could impact windshield visibility in cold or humid conditions. Repair at convenience unless defrost function is compromised.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1968 to identify the root cause.
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Quick Info
Category
Body
System
Climate Control System
Difficulty
Type
Manufacturer
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