Circuit Description
DTC C1236 monitors the voltage level available to the EBCM controller. If the voltage drops below 11.2 volts, full performance of the ABS system is not guaranteed. During ABS operation, there are several current requirements that will cause battery voltage at the EBCM to drop. As a result, voltage is monitored prior to an ABS event to indicate good charging system condition. Voltage is also monitored during an ABS event when voltage may drop significantly.
Conditions for Setting the DTC
| • | DTC C1236 can set only if the vehicle's speed is greater than 5 km/h (3 mph). |
| • | A malfunction exists if both the switched battery and switched ignition voltages are less than 11 volts during non-ABS event, or less than 9 volts during an ABS event. |
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
The following conditions may cause a malfunction:
| • | A poor connection |
| • | Rubbed-through wire insulation |
| • | A broken wire inside the insulation |
| • | Vehicle's charging system is not operating properly (low generator output, faulty battery) |
| • | High resistance in the switched ignition or switched battery circuits |
| • | Poor G102 |
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
Thoroughly inspect any circuitry that may be causing 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 |
While performing a Voltage Load test, the switched ignition circuit should be measured for high resistance or an open condition if it is noted that only the ignition voltage drops below acceptable voltage levels.
Ensure the starting and charging systems are in proper working order. The battery should be fully charged and in good condition before beginning the diagnostic table. Refer to Charging System Check in Engine Electrical.
Test Description
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This test checks for excessive resistance in the switched battery input circuit.
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This test checks for excessive resistance in the battery feed circuit.
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This test checks for an open or high resistance in the switched ignition circuit.
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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 A Diagnostic System Check-ABS performed? | -- | ||||||||||||||||||
2 |
Are the ignition voltage and the battery voltage equal to or greater than the specified voltage? | 10 V | ||||||||||||||||||
Is the resistance within the specified range? | 0-2 ohms | |||||||||||||||||||
Is the resistance within the specified range? | 0-2 ohms | |||||||||||||||||||
Is the resistance within the specified range? | 0-2 ohms | |||||||||||||||||||
6 | Use the J 39200 in order to measure the resistance between the fuse block terminal (DEF Fuse [20A]) and the EBCM connector terminal A9. Is the resistance within the specified range? | 0-2 ohms | ||||||||||||||||||
7 |
Are there signs of terminal damage, poor terminal contact, or terminal corrosion? | -- | ||||||||||||||||||
Does DTC C1236 set as a current DTC? | -- | |||||||||||||||||||
9 | Repair the open or high resistance in the WHT wire between the relay box and the EBCM. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||||||||||
10 | Repair the open or high resistance in the WHT/BLU wire between the fuse box and the relay box. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||||||||||
11 | Repair the open or high resistance in the YEL/GRN wire between the junction block and the EBCM. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||||||||||
12 | Repair the open or high resistance in the power feed circuits to the fuse block. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||||||||||
13 | Replace all of the terminals or the connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminals. Refer to Connector Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||||||||||||
14 | Repair the low voltage condition. Refer to Charging System Check in Engine Electrical. Is the low voltage condition repaired? | -- | -- | |||||||||||||||||
15 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | -- | |||||||||||||||||
16 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | System OK | -- | ||||||||||||||||
