Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p1492 coil 1 egr "a" control circuit low

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h4do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p1492 coil 1 egr "a" control circuit low

NOTE:

For the diagnostic procedure, refer to DTC P1498. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P1498 COIL 4 EGR "A" CONTROL CIRCUIT LOW

1. OUTLINE OF DIAGNOSIS

Detects open or short circuit of EGR.

Judge as NG when the ECM output level differs from the actual terminal level.

2. COMPONENT DESCRIPTION

(1)	Engine control module (ECM)	(4)	Switch circuit	(6)	Main relay
(2)	Computer unit (CPU)	(5)	Battery voltage	(7)	EGR control valve
(3)	Detecting circuit

3. EXECUTION CONDITION

Secondary Parameters	Execution condition
Battery voltage	≥ 10.9 V
EGR drive signal	OFF

4. GENERAL DRIVING CYCLE

Perform the diagnosis continuously after the enable conditions have been established.

5. DIAGNOSTIC METHOD

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
EGR terminal voltage	≤ Battery voltage - 0.34

Time Needed for Diagnosis: 2500 ms

Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

Dtc p1493 coil 1 egr "a" control circuit high

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Other materials:

Inspection
1. Check that the main relay has no deformation, cracks or other damages.2. Measure the resistance between main relay terminals.Terminal No.Standard1 and 31 M- or more2 and 480.55 — 98.45 - (when 20°C (68°F))3. Connect battery positive terminal to terminal No. 2 and battery ground te ...