13A-DTC P21DB: Injector Circuit Low Input - Cylinder 1 (direct fuel injection)

DTC P21DB: Injector Circuit Low Input - Cylinder 1 (direct fuel injection)

warning

Since the injector (high pressure) drive circuit is high voltage and there is a danger of electric shock, do not measure the terminal voltage.

CIRCUIT OPERATION

Power is supplied to the No. 1 cylinder injector (high pressure) from the ECM connector terminal DI+1.
The ECM connector terminal DI-1 makes the power transistor in the unit be in ON position, and that makes currents go on the No. 1 cylinder injector (high pressure).

TECHNICAL DESCRIPTION

The ECM controls the power supply interval of the injector (high pressure).
The fuel injection amount of the injector (high pressure) depends on the power supply interval.

DESCRIPTIONS OF MONITOR METHODS

The ECM detects open circuit and short malfunction.

MONITOR EXECUTION

Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC set in memory for the item monitored below)

Not applicable

Sensor (The sensor below is determined to be normal)

Not applicable

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

Ignition switch is "ON" position.
After 2 seconds pass from the time when the engine is stopped.
Battery positive voltage is between 10 and 16.5 volts.
Power supply voltage for injector (high pressure) driver is more than 10 volts.

Judgment Criterion

A malfunction by open circuit/short to ground occurred for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

Prohibit driving the malfunctioning cylinder injector and injector (high pressure).

While prohibiting the operation of the injector (high pressure), carry out the control by the injector operation only.
Torque is restricted.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

No. 1 cylinder injector (high pressure) failed.
Open or shorted No. 1 cylinder injector (high pressure) circuit, harness damage or connector damage.
ECM failed.

DIAGNOSIS

STEP 1. Check the No. 1 cylinder injector (high pressure) resistance at intermediate connector.

(1) Disconnect the intermediate connector and measure at No. 1 cylinder injector (high pressure) side.

(2) Measure the resistance between terminal DI+1 and DI-1.

Resistance should be between 1.74 and 2.04 ohms [at 20° (68°F)].

Is the measured resistance between 1.74 and 2.04 ohms [at 20C (68F)]?

Go to Step 5

Go to Step 2

STEP 2. Check of open circuit and harness damage in DI+1 line between injector (high pressure) intermediate connector and No. 1 cylinder injector (high pressure) connector.

Is the harness wire in good condition?

Go to Step 3

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 3. Check of open circuit and harness damage in DI-1 line between injector (high pressure) intermediate connector and No. 1 cylinder injector (high pressure) connector.

Is the harness wire in good condition?

Go to Step 4

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 4. Check the No. 1 cylinder injector (high pressure).

Refer to No. 1 Cylinder Injector (high pressure) Check

Is the measured resistance normal?

It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions

Replace the No. 1 cylinder injector (high pressure). Then go to Step 10

STEP 5. Check of short circuit to ground in DI+1 line between injector (high pressure) intermediate connector and No. 1 cylinder injector (high pressure) connector.

Is the harness wire in good condition?

Go to Step 6

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 6. Check of short circuit to ground in DI-1 line between injector (high pressure) intermediate connector and No. 1 cylinder injector (high pressure) connector.

Is the harness wire in good condition?

Go to Step 7

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 7. Check of open circuit and harness damage in DI+1 line between injector (high pressure) intermediate connector and ECM connector.

Is the harness wire in good condition?

Go to Step 8

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 8. Check of short circuit to ground, open circuit and harness damage in DI-1 line between injector (high pressure) intermediate connector and ECM connector.

Is the harness wire in good condition?

Go to Step 9

Repair the connector(s) or wiring harness. Then go to Step 10

STEP 9. Check the trouble symptoms.

(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1

(2) Check the diagnostic trouble code (DTC).

Is DTC P21DB set?

Replace the ECM (Refer to Removal and Installation

). Then go to Step 10

It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions

STEP 10. Test the OBD-II drive cycle.

(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1

(2) Check the diagnostic trouble code (DTC).

Is DTC P21DB set?

Retry the troubleshooting.

The inspection is complete.