Circuit Description
DTC C1248 detects a stripped nut or gear assembly during initialization. During the homing sequence, the piston should reach the top of the bore. Then the ABS motor stalls. If the ABS motor does not stall, the ABS motor must be spinning with little or no resistance. This indicates a nut/screw or gear malfunction.
Conditions for Setting the DTC
DTC C1248 can only set during initialization.
A malfunction exists if the feedback current is less than the command current for a specified period of time.
Action Taken When the DTC Sets
| • | A malfunction DTC stores. |
| • | The ABS disables. |
| • | The ABS warning indicator turns 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 DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF. |
Diagnostic Aids
An intermittent malfunction in this DTC may result from a mechanical part of the system that slips, such as a backed off gear retaining nut.
Depending on the frequency of the malfunction, a physical inspection of the mechanical parts suspected of causing the malfunction may be necessary.
Test Description
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This test checks for motor movement by comparing the motor feedback current to the motor command current during apply.
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This test checks for motor movement by comparing the motor feedback current to the motor command current during release.
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This test checks for piston movement.
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This test checks for excessive resistance in the right front motor high circuit.
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This test checks for excessive resistance in the right front motor low circuit.
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This test checks for the proper right front motor resistance value.
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This test checks for proper operation of the motor pack.
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This test checks for proper operation of the hydraulic modulator.
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This test determines if the malfunction is caused by the EBCM.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual. | ||||||||||||
1 | Was the ABS Diagnostic System Check performed? | -- | Go to Step 2 | |||||||||
2 |
Do not start the engine. Does DTC C1261 also set as a current DTC? | -- | Go to Step 3 | |||||||||
Observe the following currents:
Were the right front ABS motor command current and the right front ABS motor feedback current approximately the specified current? | 10 A | Go to Step 4 | Go to Step 6 | |||||||||
Observe the following currents:
Have the following conditions been met?
| 6 A | Go to Step 5 | Go to Step 6 | |||||||||
Did the brake pedal rise? | -- | Go to Step 22 | Go to Step 6 | |||||||||
Is the resistance within the specified range? | 0-2 ohms | Go to Step 7 | Go to Step 15 | |||||||||
Use the J 39200 in order to measure the resistance between the ABS brake motor pack connector terminal F and the EBCM connector terminal B. Is the resistance within the specified range? | 0-2 ohms | Go to Step 8 | Go to Step 16 | |||||||||
Use the J 39200 in order to measure the resistance between the ABS brake motor pack connector terminal E and the ABS brake motor pack connector terminal F. Is the resistance within the specified range? | 0.2-1.5 ohms | Go to Step 9 | Go to Step 17 | |||||||||
9 |
(The ABS brake motor pack is the unit with the three small gears. The ABS brake motor pack right front gear is the gear closest to the rear when the ABS brake modulator is mounted in the vehicle.) Is the ABS brake motor right front gear stripped? | -- | Go to Step 17 | Go to Step 10 | ||||||||
10 | Inspect for a stripped ABS brake modulator right front gear. (The ABS brake modulator unit is the unit with the three large gears. The ABS brake modulator right front gear is the gear closest to the rear when the ABS brake modulator is mounted in the vehicle.) Is the ABS brake modulator right front gear stripped? | -- | Go to Step 18 | Go to Step 11 | ||||||||
Secure the assembly in a position that permits observation of the gears. Do not start the engine. (The ABS brake modulator right front gear is the gear closest to the rear when the ABS brake modulator is mounted in the vehicle.) Does the ABS brake modulator right front gear set move at least one full revolution in both directions? | -- | Go to Step 12 | Go to Step 17 | |||||||||
Does the ABS brake modulator right front gear rotate more than 13 full turns from lock to lock? | -- | Go to Step 19 | Go to Step 13 | |||||||||
13 |
Do any of the terminals exhibit poor terminal contact or corrosion? | -- | Go to Step 20 | Go to Step 14 | ||||||||
Does DTC C1248 set as a current DTC? | -- | Go to Step 21 | Go to Step 22 | |||||||||
15 | Repair the high resistance in CKT 1282. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||
16 | Repair the high resistance in CKT 1283. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||
17 | Replace the ABS brake motor pack. Refer to ABS Motor Pack Replacement . Is the repair complete? | -- | -- | |||||||||
18 | Replace the ABS brake modulator gear. Refer to Brake Modulator Gear Replacement . Is the repair complete? | -- | -- | |||||||||
19 | Replace the ABS brake modulator. Refer to Brake Pressure Modulator Valve Assembly Replacement . Is the repair complete? | -- | -- | |||||||||
20 | Replace the terminals that exhibit signs of poor terminal contact or corrosion. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||
21 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- | |||||||||
22 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | System OK | -- | ||||||||
