Two issues the p1402 is an EGR issue . The valve sticking etc .
P1402 - EGR function (Open)
- Engine Light ON (or Service Engine Soon Warning Light)
- The EGR volume control valve circuit is open or shorted
- EGR volume control valve leaking or stuck open
- EGR temperature sensor
Start by cleaning the EGR valve, if the code persist it may be necessary to replaced the EGR Valve
- Clean EGR Valve
- Replaced EGR Valve
When is the code detected?
EGR flow is detected under the condition that does not call for EGR.
This system controls flow rate ofEGR led from exhaust manifold to intake manifold. The opening of the EGR by-pass passage in theEGR volume control valve changes to control the flow rate. A built-in step motor moves the valve in steps corresponding to the ECM output pulses. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is determined by considering various engine conditions. The EGR volume control valve remains closed under the following conditions.
- Engine stopped
- Engine starting
- Engine idling
- Low engine coolant
- Excessively high engine coolant temperature
- High engine speed
- Wide open throttle
- Low battery voltage
The p0171 is a faulty mass air flow sensor . These need to be checked next for this issue . The knock sensor will not cause this issue. These are the next steps. Hoped this helped . Positive feedback and bonuses greatly appreciated.