Tech Tips March 2016 (TIPS0316)

TECH TIPS MARCH 2016

TECHNICAL SERVICE BULLETIN

01 QMR OF THE MONTH

We are pleased to announce this month's winner of QMR of the Month:

David submitted a very detailed QMR on his diagnosis and repair of a 2014 Legacy with 21K miles. The customer reported the remote door mirrors would not work and the back-up (reverse) lamps were not illuminating. Based upon the complaint, David started his diagnosis with a check for codes and confirmation of both symptoms. Inspections confirmed the conditions and made him suspect a wiring failure. A review of the related wiring diagrams for both components led David to find fuse 6 for the mirror switch and fuse 18 for the back-up lamps were both open. As he reviewed the wiring diagrams for the remote control mirror system and back-up light system, there did not appear to be any connection between the two. His next stop was the Power Supply circuit diagram. Here he found fuse 6 also powers the rear view mirror (without Homelink). At this point, he noted the compass in the mirror was not illuminated. This lead him to review the rearview mirror system diagram. It was here that he found the connection, as the mirror was powered from both fuses 6 and 18. Thinking about it, this made sense as all Subaru auto-dimming mirrors are designed to stop dimming whenever reverse is selected. Further checks confirmed the mirror was the source of the short to ground. Removing the mirror David found that a necklace the customer had hanging from it had worked its way into the mirror housing and created a short on the circuit board damaging it. Once David replaced the mirror and installed new fuses, the related circuits all functioned correctly. This report was a good example of electrical diagnosis and demonstrates how circuits which seem unrelated at first, may be connected by exploring the related circuits as found in the Power Supply circuit diagram. David's report included extensive detail with photos and copies of the various circuit and Power Supply circuit diagrams helping to explain his step by step diagnosis. This detail made it very clear how he arrived at the final result.

In appreciation for going the extra mile and sharing his experience with us, David will be receiving the following from his FSE:

07 SPARK PLUG INFORMATION & A REMINDER

Both the Techline and Claims Group have been receiving a number of calls recently asking about spark plug coverage when performing engine repairs, especially since release of the WQW-58R Service Program Bulletin. When removing the spark plugs, and to avoid damaging the porcelain insulator, it is imperative to ALWAYS use the right tool for the job (e.g. a Snap-On S9714MKR or equivalent dedicated spark plug socket) and NOT a regular 14mm deep-well socket. Use of a standard socket or a spark plug socket that has a missing or loose rubber insert can result in plug damage.

There have also been inquiries about a brownish-colored ring or stain which develops on the insulator between the top of the steel body (hex portion) of the plug and the bottom of the silicone coil or plug wire boot. This discoloration is called a "Corona Stain" and is NOT an indicator of compression leakage. It is often seen on spark plugs which are installed deep into the engine such as on many four valves per cylinder engine applications where oil particles do not get blown away by air circulating around the engine compartment. When coupled with the high voltage pulsing inside the spark plug insulator, the particles will often adhere to the insulator surface and develop the stain as shown in these photo above. This phenomenon is normal and does not compromise function of the spark plug in any way.

07 BATTERY SERVICING PRECAUTIONS

If there is ever a need to service a Subaru battery, always use distilled water. Tap water can contain chemicals/heavy metals that could potentially harm the battery. Always refer to the applicable Service Manual before proceeding with any repairs.

The example below is directly from the Service Manual of a 2010 Legacy.

1. 2. ELECTROLYTE LEVEL 

   Check the electrolyte level in each cell. If the level is below MIN level, bring the level to MAX level pouring distilled water into the batter cell. Do not Fill beyond MAX level.

   Caution  must be used to avoid overfilling a battery. If the fluid level is increased beyond the Max level this can result in battery swelling, cracking, or leakage.

15 ACCESSORY DOOR EDGE GUARD REMOVAL PROCESS

Accessory Door Edge Guards are designed to protect the door edge in the high impact areas. They are painted with a special polymer, and are available for most of our model line-up. If, for some reason, a customer requests a Door Edge Guard replacement and the original is still in place, it will need to be removed using the following process to prevent paint and/or door edge damages.

Start by positioning the tip of a plastic trim tool as shown in figure 1, against the leading edge of the Door Edge Guard on the exterior door surface. Begin tapping the tool gently, starting from the top of the Door Edge Guard to separate the accessory from the door. Continue to tap and separate the Door Edge Guard from the door itself until about 3" above the bottom of the accessory. Once at this point, place the tip of the tool at the bottom of the Door Edge Guard and begin tapping while working your way upward until the accessory is removed. If the Door Edge Guard requires removal for any reason, reuse is not recommended as the fitment is not guaranteed once removed.