DTC C1221 LF Wheel Speed Sensor Input Signal is 0. Cadillac Seville 1998

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 DTC 🢒 DTC C1221 LF Wheel Speed Sensor Input Signal is 0

ABS Components
Cell 44: Wheel Speed Sensors
Handling ESD Sensitive Parts Notice

Circuit Description

The wheel speed sensor used on this vehicle is a single point magnetic pickup. This sensor produces an AC signal that the EBTCM uses the frequency from to calculate the wheel speed.

Conditions for Setting the DTC

All of the following conditions exists for 2.5 seconds:

•	The suspect wheel speed equals zero.

•	The other wheel speeds are greater than 8 km/h (5 mph).

•	The other wheel speeds are within 11 km/h (7 mph) of each other.

Action Taken When the DTC Sets

•	A malfunction DTC is stored.

•	The ABS/TCS/Stabilitrak® is disabled.

•	The ABS indicator is turned ON.

•	The TRACTION CONTROL indicator is turned ON.

•	The DIC displays the SERVICE STABILITY SYS message.

Conditions for Clearing the DTC

•	The condition for DTC is no longer present and you used scan tool Clear DTCs function.

•	The condition for DTC is no longer present and you used the On-Board Clear DTCs function.

•	The EBTCM does not detect the DTC in 50 drive cycles.

Diagnostic Aids

•	It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

•	An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.

•	If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Test Description

The numbers below refer to step numbers on the diagnostic table.

Checks the resistance of the wheel speed sensor.

Checks if the wheel speed sensor circuits are shorted together.

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check?	--	Go to Step 2	Go to Diagnostic System Check
2	Inspect the wheel speed sensor wiring and connectors for damage. Inspect the wheel speed sensor for looseness or damage. Is physical damage of sensor evident?	--	Go to Step 7	Go to Step 3
3	Disconnect the wheel speed sensor connector. Using a J 39200 DMM, measure the resistance between the wheel speed sensor terminals A and B. Is the resistance within the specified range?	850-1350 ohms	Go to Step 4	Go to Step 7
4	With the J 39200 DMM still connected, select the mV AC scale. Spin the wheel as fast as you can by hand while monitoring the AC output. Is the AC voltage greater than the specified value?	100 mV	Go to Step 5	Go to Step 7
5	Disconnect the EBTCM harness connector. Install the J 39700 universal pinout box using the J 39700-25 cable adapter to the EBTCM harness connector only. Using a J 39200 DMM, measure the resistance between the J 39700 terminals 15 and 31. Is the resistance within the specified range?	OL (Infinite)	Go to Step 6	Go to Step 8
6	Reconnect all connectors. Carefully test drive the vehicle above 24 Km/h (15 mph) for at least 30 seconds while monitoring a scan tool. Does the DTC set as a current DTC?	--	Go to Step 9	Go to Diagnostic System Check
7	Replace the wheel speed sensor. Refer to Front Wheel Bearing and Hub Replacement in Front Suspension. Did you complete the repair?	--	Go to Step 10	--
8	Repair the short between CKT 873 and CKT 830. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?	--	Go to Step 10	--
9	Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair?	--	Go to Step 10	--
10	Carefully test drive the vehicle above 24 Km/h (15 mph) for at least 30 seconds while monitoring a scan tool. Does the DTC set as a current DTC?	--	Go to Step 2	Go to Diagnostic System Check