Jump to content

need some help


Recommended Posts

Hello everyone. I’m new here and I need some help. I have a service engine soon light that keeps coming on. The truck has been to the shop twice for this already and Monday will make it the third time. I had Auto Zone check it for me and they say the codes are P1412 and P1415. The truck is a 2002 Discovery II se with the 4.0 V8. Do any of you have an idea on what these codes are or what could be causing them to keep coming up? Thanks for the help.

Link to comment
Share on other sites

Welcome :)

Secondary air injection fault - codes below:

P-code Description

P1412 SAI system fault (LH side) - air delivery not reaching catalysts

P1414 SAI system fault (LH side) - air delivery not reaching catalysts

P1413 SAI system fault (LH side) - air delivery not reaching catalysts

P1415 SAI system fault (RH side) - air delivery not reaching catalysts

P1417 SAI system fault (RH side) - air delivery not reaching catalysts

P1416 SAI system fault (RH side) - air delivery not reaching catalysts

From RAVE:

Secondary air injection system

The secondary air injection (SAI) system comprises the following components:

l Secondary air injection pump

l SAI vacuum solenoid valve

l SAI control valves (2 off, 1 for each bank of cylinders)

l SAI pump relay

l Vacuum reservoir

l Vacuum harness and pipes

The secondary air injection system is used to limit the emission of carbon monoxide (CO) and hydrocarbons (HCs)

that are prevalent in the exhaust during cold starting of a spark ignition engine. The concentration of hydrocarbons

experienced during cold starting at low temperatures are particularly high until the engine and catalytic converter

reach normal operating temperature. The lower the cold start temperature, the greater the prevalence of

hydrocarbons emitted from the engine.

There are several reasons for the increase of HC emissions at low cold start temperatures, including the tendency for

fuel to be deposited on the cylinder walls, which is then displaced during the piston cycle and expunged during the

exhaust stroke. As the engine warms up through operation, the cylinder walls no longer retain a film of fuel and most

of the hydrocarbons will be burnt off during the combustion process.

The SAI pump is used to provide a supply of air into the exhaust ports in the cylinder head, onto the back of the

exhaust valves, during the cold start period. The hot unburnt fuel particles leaving the combustion chamber mix with

the air injected into the exhaust ports and immediately combust. This subsequent combustion of the unburnt and

partially burnt CO and HC particles help to reduce the emission of these pollutants from the exhaust system. The

additional heat generated in the exhaust manifold also provides rapid heating of the exhaust system catalytic

converters. The additional oxygen which is delivered to the catalytic converters also generate an exothermic reaction

which causes the catalytic converters to 'light off' quickly.

The catalytic converters only start to provide effective treatment of emission pollutants when they reach an operating

temperature of approximately 250C (482F) and need to be between temperatures of 400C (752F) and 800C

(1472F) for optimum efficiency. Consequently, the heat produced by the secondary air injection “afterburning”,

reduces the time delay before the catalysts reach an efficient operating temperature.

The engine control module (ECM) checks the engine coolant temperature when the engine is started, and if it is below

60º C (131F), the SAI pump is started. Secondary air injection will remain operational for a period controlled by the

ECM (76 seconds for NAS vehicles, 64 seconds for EU-3 vehicles). The SAI pump operation can be cut short due to

excessive engine speed or load.

Air from the SAI pump is supplied to the SAI control valves via pipework and an intermediate T-piece which splits the

air flow evenly to each bank.

At the same time the secondary air pump is started, the ECM operates a SAI vacuum solenoid valve, which opens to

allow vacuum from the reservoir to be applied to the vacuum operated SAI control valves on each side of the engine.

When the vacuum is applied to the SAI control valves, they open simultaneously to allow the air from the SAI pump

through to the exhaust ports. Secondary air is injected into the inner most exhaust ports on each bank.

When the ECM breaks the ground circuit to de-energise the SAI vacuum solenoid valve, the vacuum supply to the

SAI control valves is cut off and the valves close to prevent further air being injected into the exhaust manifold. At the

same time as the SAI vacuum solenoid valve is closed, the ECM opens the ground circuit to the SAI pump relay, to

stop the SAI pump.

A vacuum reservoir is included in the vacuum line between the intake manifold and the SAI vacuum solenoid valve.

This prevents changes in vacuum pressure from the intake manifold being passed on to cause fluctuations of the

secondary air injection solenoid valve. The vacuum reservoir contains a one way valve and ensures a constant

vacuum is available for the SAI vacuum solenoid valve operation. This is particularly important when the vehicle is at

high altitude.

As for why, sorry I have no experience of these SAI systems as they are only fitted to NAS spec vehicles :(

Mind you a V8 fitted with afterburners sounds like fun :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy