LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2007 >> Swift + >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System >> Diagnostic Information and Procedures >> DTC C1201 >> Diagnostic Aids
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Aids

Thoroughly inspect the wiring and connectors when diagnosing intermittent DTCs. This will include the following:

If the driver comments reflect that the ABS warning lamp is ON only during moist environmental changes, such as rain, snow, vehicle wash, the all wheel speed sensor circuitry should be thoroughly inspected for signs of water intrusion. If the DTC is not current, simulate the effects of water intrusion. Use the following procedure. Spray the suspected area with a 5 percent salt-water solution. Then test drive the vehicle over various road surfaces such as bumps, turns, etc., above 24 km/h (15 mph). If the DTC sets then replace the suspected harness and/or sensor.

A careful visual inspection of the wheel speed sensor for damage such as cracks should be performed. If the DTC sets at the same speed every drive cycle, the toothed ring is most likely damaged.

Failure to perform the previous steps carefully and fully can result in misdiagnosis, unnecessary component replacement, and reoccurrence of DTC C1201.

DTC C1201

Step Action Values Yes No
Schematic Reference:  Antilock Brake System Schematics (Notchback)   or  Antilock Brake System Schematics (Hatchback)  
Connector End View Reference:  Antilock Brake System Connector End Views (Notchback)   or  Antilock Brake System Connector End Views (Hatchback)  
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 Was the DTC C1200 set as a current or history DTC? - Go to DTC C1200  Go to Step 3 
3
  1. Turn the ignition switch OFF.
  2. Inspect the left front wheel speed sensor and the jumper harness for damage.
  3. Perform a complete and thorough inspection of the left front wheel speed sensor for damage, such as, cracks, missing teeth, looseness.
Is any physical damage noted?		 - Go to Step 4  Go to Step 5 
4 Repair the damage to the left front wheel speed sensor, and/or jumper harness.
Did you find and correct the condition?		 - Go to Step 19  -
5
  1. Put the vehicle in park or neutral and set the parking brake.
  2. Connect a scan tool and select the data list.
  3. Monitor the wheel speed sensors.
  4. Start the vehicle, and monitor the wheel speed sensors with the engine running but the vehicle not moving.
  5. Lightly depress the accelerator pedal to increase the engine idle speed.
Did the DTC C1201 reset or did the left front wheel speed read above 0 mph when the vehicle was in park with the engine running?		 - Go to Step 6  Go to Step 7 
6
  1. The cause of the DTC C1201 is ignition noise coupled onto the left front speed sensor circuits.
  2. Inspect the routing of the left front ABS body harness and/or jumper harness for potential ignition noise sources such as spark plug wires.
  3. Reroute the wiring as needed.
Did you find and correct the condition?		 - Go to Step 19  -
7
  1. The scan tool is still connected.
  2. Monitor the wheel speed sensors.
  3. Test drive the vehicle up to the maximum-posted speed limit, and slowly decelerate to 0. Do this several times.
Did DTC C1201 reset or did the left front wheel speed vary more than 5 km/h (3 mph) when compared to any one of the other wheels during the drive?		 - Go to Step 8  Go to Diagnostic Aids
8
  1. Put the vehicle in park or neutral and turn the ignition switch OFF.
  2. Raise and suitably support the vehicle.
  3. Disconnect the left front jumper harness from the left front wheel speed sensor.
  4. Connect an ohmmeter to terminals 2 and 1 of the left front wheel speed sensor.
  5. Resistance will vary with temperature.
Is the resistance within the specified range?		 800-1600 Ω Go to Step 10  Go to Step 9 
9 Replace the left front wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement .
Did you complete the replacement?		 - Go to Step 19  -
10
  1. The speed sensor is still disconnected from the jumper harness.
  2. Connect a voltmeter to terminal 2 and 1 of the left front speed sensor.
  3. Select the AC millivolt scale.
  4. Spin the left front wheel while observing the voltage on the meter.
Is the AC voltage greater than the specified value?		 100 mV Go to Step 11  Go to Step 9 
11
  1. Disconnect the electronic brake control module (EBCM) harness from the EBCM.
  2. Disconnect the left front jumper harness from the ABS body harness.
  3. Connect an ohmmeter to the EBCM harness from the ABS body harness.
  4. Connect an ohmmeter to the EBCM harness terminal 20 and then to ABS body harness terminal 2.
Is the resistance measured less than the specified value?		 2 Ω Go to Step 13  Go to Step 12 
12 Repair the source open or high resistance between terminals 20 and 2.
Did you find and correct the condition?		 - Go to Step 19  -
13
  1. The EBCM harness is still disconnected from the EBCM.
  2. The jumper harness is still disconnected from the body harness.
  3. Connect an ohmmeter to the EBCM harness terminal 19 and then to ABS body harness terminal 1.
Is the resistance measured less than the specified value?		 2 Ω Go to Step 15  Go to Step 14 
14 Repair the open or high resistance between terminals 19 and 1.
Did you find and correct the condition?		 - Go to Step 19  -
15
  1. The EBCM harness is still disconnected from the EBCM.
  2. The jumper harness is still disconnected from the body harness.
  3. Connect an ohmmeter between EBCM harness terminals 20 and 19.
Is the resistance within the specified value?		 OL (open circuit) Go to Step 17  Go to Step 16 
16 Repair the short between the two wires.
Did you find and correct the condition?		 - Go to Step 19  -
17
  1. Replace the left front jumper harness.
  2. Test drive the vehicle at various speeds and road surfaces.
Did DTC C1201 reset?		 - Go to Step 18  Go to Step 19 
18 Replace the EBCM. Refer to Brake Modulator Assembly Replacement .
Did you complete the replacement?		 - Go to Step 19  -
19
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
scientia non olet · About LEMON Manuals