P0267 Cylinder 3 Injector Circuit Low - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

Based on information from various sensors, the ECM controls the amount of fuel sent to the cylinder via the fuel injection system. The fuel injector is a solenoid-operated valve that meters the fuel. The ECM controls by length of time the fuel injector is held open. The ECM grounds the injector control circuit to open the injector. When the ECM energizes the injector by grounding the control circuit, the circuit voltage should be pulled low (theoretically 0V) and the fuel is injected. When the ECM de-energizes the injector by opening the control circuit, the fuel injector is closed and circuit voltage should momentarily peak before settling back to system voltage.

DTC DESCRIPTION

Checking output signals from injectors. Under detecting condition, if an output signal is low, ECM sets P0267.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible Cause

DTC Strategy

Signal Low

1.	Poor connection

2.	Open or short to ground in power harness

3.	Open or short to ground in control harness

Injector

ECM

Enable Conditions

Engine running state

11V ≤ Battery voltage ≤ 16V

Above conditions are met > 0.5sec.

Threshold value

Open or short to ground

Diagnosis Time

Continuous (more than 5 sec. failure for every 10 sec.test)

MIL On Condition

3 Driving Cycles

SPECIFICATION

Item	Coil resistance(Ω)
Injector	13.8 ~ 15.2 [20°C(68°F)]

DIAGNOSTIC CIRCUIT DIAGRAM

SIGNAL WAVEFORM & DATA

Fig.1) Normal waveforms of Injector under idle condition.

When the ECM energizes the injector by grounding control circuit, the circuit voltage should be low (theoretically 0V) and the fuel is injected. When the ECM de-energizes the injector by opening control circuit, the fuel injector is closed and circuit voltage should be peak at a moment.

MONITOR GDS DATA

1.	Connect GDS to Data Link Connector(DLC).

IG “ON”.

3.	Select “DTC” button, and then Press “DTC Status” to check DTC’s information from the DTCs menu.

4.	Read “DTC Status” parameter.

Is parameter displayed “Present fault”?

	▶ Go to “Terminal and Connector inspection” procedure.
	▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to “Verification of Vehicle Repair” procedure .
	▶ Go to ” Power Circuit Inspection ” procedure.

POWER CIRCUIT INSPECTION

■ Check voltage

1.	IG “OFF” and disconnect injector connector.

IG “ON”.

Measure voltage between power terminal of injector harness connector and chassis ground.

Approx. B+

Is the measured voltage within specification ?

	▶ Go to “Control Circuit Inspection” procedure.
	▶ Check open or connection of the fuse connected to injector power supply. ▶ Repair open or short to ground in harness, and go to “Verification of Vehicle Repair’ procedure.

CONTROL CIRCUIT INSPECTION

■ Check short to ground in harness

1.	IG “OFF” and disconnect injector connector and ECM connector.

Measure resistance between injector control terminal of injector harness connector and chassis ground.

Infinite

Is the measured resistance within specification ?

	▶ Go to “Check open in harness” as follows.
	▶ Repair short to ground in harness, and go to “Verification of Vehicle Repair” procedure.

■ Check open in harness

1.	IG “OFF” and disconnect injector connector and ECM connector.

Measure resistance between injector control terminal of injector harness connector and injector control terminal of ECM harness connector.

Below 1Ω

Is the measured resistance within specification ?

	▶ Go to “Component Inspection” procedure.
	▶ Repair open in harness

COMPONENT INSPECTION

■ Check injector

1.	IG “OFF” and disconnect injector connector.

Measure resistance between power and control terminals of injector connector.(Component side)

13.8 ~ 15.2Ω [20°C(68°F)]

Is the measured resistance within specification ?

▶ Substitute with a known – good ECM and check for proper operation. If the problem is corrected, replace ECM and go to “Verification of Vehicle Repair” procedure.

There is a memory reset function on GDS that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others

▶ Substitute with a known – good Fuel Pump Relay and check for proper operation. If the problem is corrected, replace Fuel Pump Relay

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