GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Epica 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 DTC 049

Circuit Description

The electronic control module (ECM) monitors the battery voltage at the ECM connector terminal C16. If the ECM detects voltage above the tolerance, the DTC 049 will be set.

Conditions for Setting the DTC

The battery voltage is greater than 17.2 volts for more than 2 seconds.

Diagnostic Aids
    • Charging the battery with a battery charger and starting the engine may set DTC 049.
    • Inspect the ECM wiring harness connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and a damaged harness.
    • If the connections and the wiring harness are OK, monitor the battery voltage display on the scan tool while moving related connectors. If the fault is induced, the battery voltage will abruptly change. This may help to isolate the location of the problem.

Step

Action

Values

Yes

No

1

Was the Diagnostic System Check performed?

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Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Connect the scan tool to the data link connector (DLC).
  2. Start the engine and raise the engine speed to 1,200 RPM.
  3. Monitor the battery voltage on the scan tool.

Is the voltage at or above the value specified?

17.2 V

Go to Step 3

Go to Step 4

3

Measure the voltage across the battery.

Is the voltage at or above the value specified?

17.2 V

Go to Step 5

Go to Step 6

4
  1. Turn the headlamps ON.
  2. Turn the A/C ON.
  3. Turn the blower switch to HIGH.
  4. Raise the engine speed to 2,000 RPM.
  5. Monitor the battery voltage on the scan tool.

Is the voltage at or above the value specified?

17.2 V

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn the ignition to LOCK.
  2. Repair the generator or generator circuit as needed.
  3. Clear any DTCs from the engine control module (ECM).
  4. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

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6
  1. Replace the ECM. Refer to Engine Control Module Replacement .
  2. Repair the generator or generator circuit as needed.
  3. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

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