Diagnostic Trouble Code (DTC) P0261

Injector 1 Low Voltage

 

 

Circuit Highlights

 

  • There are four individual injector driver circuits found in the transaxle control module (TCM)/engine control module (ECM) and each of these four controls an injector.
  •  The injector is activated each time the ECM grounds a driver circuit.
  •  The ECM checks the current in each driver circuit.
  •  A fixed resistor helps the ECM to measure any fall in the voltage and control it subsequently.
  • The voltage on each driver is capable of identifying any fault.
  •  A Diagnostic Trouble Code (DTC) will set when the voltage does not tally with the ideal voltage the ECM is empowered to monitor on the circuit.
  •  This DTC also identifies a low voltage and/or an open circuit and high voltage conditions for low-side drive injector outputs.

 

 

 

When does DTC set?

Task boosted after DTC sets

When will DTC clear?

 

DTC sets when:

 

1) The injector 1 circuit remains in open or a short to ground state.

 

1) The Malfunction Indicator Lamp (MIL) will be seen to glow.

 

1) The MIL will automatically get switched off after repetitive ignition cycles in which the diagnostic runs flawlessly.

 

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2) The ECM will store conditions from the time the diagnostic had failed.

 

 

2) De-linking the ECM battery feed for more than 10 seconds will also help.

 

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3) This data will be stored in the Freeze Frame.

 

3) A history DTC will unset after 40 repetitive and flawless warm up cycles.

 

 

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4) Failure Records will be boosted.

 

 

4) A Scan Tool may be used to unset all DTCs.

 

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5)  A history DTC will be recorded.

 

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Assistance in Diagnostics

 

  • DTC P0261 will set when an injector driver is open or shorted to voltage.
  • A misfire due to an inoperative injector can also occur at this stage.
  • Mentioning the inoperative injector a misfire DTC also needs to set.
  • Abnormally high or low long-term and short-term fuel trims are a good way of knowing about a malfunctioning injector.
  • For faulty injectors you may read up anything on Fuel Injector Balance Test.
  • It will be found that the injector resistance when tested at the ECM connection is a little more than if tested directly at the injector.
  • This is because it includes resistance of the harness wires.
  •  The normal value is about 13.5?©.

 

 

 

HOW TO UNSET A DTC

DTC P0261 - Injector 1 Low Voltage

 

Step

Task

Positive

Negative

1

 

Carry out the EOBD system check.

 

Task complete?

Read up

 Step 2

Read up

"On-Board Diagnostic System Check"

2

 

Start the engine.

 

Can you see that the engine starts normally?

 

Read up

 Step 3

Read up

"Engine Cranks But Will Not Run"

3

  1. Put in a scan tool.
  2. Unset all the Diagnostic Trouble Codes (DTCs).
  3. Allow the engine to idle for one minute.

Does DTC P0261 reset?

 

Read up

 Step 5

Read up

Step 4

4

  1. Read up the Freeze Frame data letting the ignition remain ON and the engine OFF.
  2. Record the parameters.
  3. Operate the car within the Freeze Frame conditions as you have recorded.

Do you see DTC P0261 resetting?

 

Read up

Step 5

Read up

"Diagnostic Aids"

5

  1. Take the ignition switch to LOCK mode.
  2. Examine and see if there is any short to ground in the wire between the injector 1 connector terminal 2 and ECM connector terminal 59.

Did you see any flaw here?

 

Read up

Step 7

Read up

 Step 6

6

  1. Take the ignition switch to LOCK mode.
  2. Examine and see if there is any short to ground in the wire between the injector 1 connector terminal 1 and battery positive.

Did you notice any fault here?

 

Read up

Step 7

Read up

 Step 8

7

  1. Mend the wire or the connector terminal if there is any fault.
  2. Unset all DTCs from ECM.
  3. Carry out the Diagnostic System Check.

Job over?

 

The system of your car is good

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8

  1. Change the injector valve.
  2. Unset all DTCs from ECM.
  3. Carry out the Diagnostic System Check.

Can you see DTC P0261 resetting?

 

Read up

Step 9

The system of your car is good

9

  1. Take the ignition switch to LOCK mode.
  2. Change the ECM.
  3. Carry out the Diagnostic System Check.

Task complete?

 

Read up

Step 10

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10

Probe whether any additional DTCs are set.

 

Do you see any undiagnosed DTCs still being shown?

Read up

applicable DTC

table

The system of your car is good