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For 1990-2009 cars only
Makes 🢒 Buick 🢒 1998 🢒 Century 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1262 RF ABS Motor Circuit Shorted to Ground

Object Number: 247742 Size: MF
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice

Circuit Description

DTC 1262 identifies an ABS motor circuit that shorts to ground. The malfunction will cause one of the following conditions to occur:

    • The ABS motor will not be controlled at the commanded current rate.
    • The driver circuit will allow current directly to the ground.

Conditions for Setting the DTC

DTC C1262 can set anytime.

A malfunction exists if The EBCM/EBCTM detects an out of range voltage on either of the right front ABS motor circuits.

An out of range voltage on either circuit indicates one of the following conditions:

    • A circuit shorts to ground.
    • An ABS brake motor internally shorts.

Action Taken When the DTC Sets
    • A malfunction DTC stores.
    • The ABS/ETS/TCS disables.
    • The amber ABS/ETS/TCS warning indicator(s) turn on.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
    • 100 drive cycles pass with no DTC(s) detected.

Diagnostic Aids

Use the Scan Tool Manual Control function in order to exercise ABS motor movement of affected channel in both directions while applying light pressure on the brake pedal.

An intermittent malfunction may be indicated if erratic or jumpy brake pedal movement is detected while performing an apply or release function of the ABS monitor.

The following conditions may cause an intermittent malfunction:

    • A poor connection
    • Rubbed-through wire insulation
    • A broken wire inside the insulation

If the malfunction is not current, use the following procedure to pinpoint an intermittent malfunction in the motor circuitry or connections:

  1. Wiggle the wires of the affected channel.
  2. Inspect if the DTC resets.

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual for the procedure.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal-to-wiring connections
    • Physical damage to the wiring harness

Clear the DTCs after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:

  1. Start the vehicle.
  2. Drive the vehicle over 16 km/h (10 mph).
  3. Stop the vehicle.
  4. Turn the ignition to the OFF position.

Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

Does DTC C1262 occur intermittently?

--

Go to Diagnostic Aids

Go to Step 3

3
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the 6-way ABS brake motor pack connector.
  3. Disconnect the 8-way EBCM/EBTCM connector C2
  4. Use the J 39200 in order to measure the resistance between the 6-way ABS brake motor pack harness connector terminal B and ground.

Is the resistance within the specified range?

OL

(Infinite)

Go to Step 4

Go to Step 9

4

Use J 39200 in order to measure the resistance between the 6-way ABS brake motor pack harness connector terminal A and ground.

Is the resistance within the specified range?

OL

(Infinite)

Go to Step 5

Go to Step 10

5

Use the J 39200 in order to measure the resistance between the 6-way ABS brake motor pack connector terminal B and ground.

Is the resistance within the specified range?

OL

(Infinite)

Go to Step 6

Go to Step 8

6
  1. Inspect the following components for damage:
    2. • The 6-way ABS brake motor pack connector
    • The 6-way ABS brake motor pack harness connector
    • Damage may cause a short to ground with the connector connected.
  2. Inspect the following components for damage:
    3. • The 8-way EBCM/EBTCM connector C2
    • The 8-way EBCM/EBTCM harness connector C2
    • Damage may cause a short to ground with the connector connected.
  3. Inspect CKT 1282 and CKT 1283 for damage. Damage may cause a short to ground.

Is there damage which may result in a short to ground?

--

Go to Step 11

Go to Step 7

7
  1. Reconnect the 6-way ABS brake motor pack connector.
  2. Reconnect the 8-way EBCM/EBTCM connector C2.
  3. Test drive the vehicle obtaining a speed at least 16 km/h (10 mph).
  4. Turn the ignition switch to the OFF position.
  5. Repeat the drive sequence two additional times.
  6. Use the Scan Tool in order to inspect for DTCs.

Did DTC C1262 set as a current DTC in the last three drive cycles?

--

Go to Step 12

Go to Step 13

8

Replace the ABS brake motor pack.

Is the repair complete?

--

Go to Diagnostic System Check

--

9

Repair the short to ground in CKT 1282.

Is the repair complete?

--

Go to Diagnostic System Check

--

10

Repair the short to ground in CKT 1283.

Is the repair complete?

--

Go to Diagnostic System Check

--

11

Replace all of the following components that exhibit signs of damage:

    • The terminals
    • The connectors
    • The wires
        Damage may cause a short to ground.

Is the repair complete?

--

Go to Diagnostic System Check

--

12

Replace the EBCM/EBTCM.

Is the repair complete?

--

Go to Diagnostic System Check

--

13

The malfunction is intermittent or not present at this time.

Is the repair complete?

--

Go to Diagnostic Aids

--