Hi guys , need some help. Honda been giving terrible mpg.

No light on dash.

When i bridge the 2p service check connector (theres a 2p & a 5p connectors ) and ignition on , the MIL and SRS dash lights stayed on. According to my Haynes manual

Code 0 means faulty PCM.

Don’t know nothing about SRS and i don’t want to pull the brain (PCM) out as i use my honda every day. Beside i don’t know nothing about electronic with all those bunch of wires.
Any insight is greatly appreciated, thank.
UK model

D16B2 series

auto

37820-P1K-E63 PCM

 

I was always under the impression that solid cel when the 2 wire connector is jumped means no codes found.

 

For God's sake... THANK YOU for this answer !!! The important distinction here is that if the CEL is off and no codes are stored, you would be correct. If the CEL is on, and when the SCS is jumped to check for codes and the CEL stays on solid without flashing, it could indicate either a "phantom code" or a damaged ECU. The ECU is basically saying "I have detected a problem but I cannot tell you what it is".

 

Thank you guys , much appreciated....
looks like the honda pcm is ok than.
my limited knowledge only allow me to do little on the honda. I nevertheless bought and waiting for (30 pounds )from ebay yesterday a second hand same pcm said to have immobilizer chip removed .
plan to have a quick swap to see what happens.... any precaution needed in changing the pcm like disconnect battery , many thanks ..... im yet to read the manual on this.

 

Disconnecting the battery would be wise with a new one going in place just for piece of mind so nothing gets fried when hooking up instead of the risk plugging into a live power source.

 

Thanks guys,
following is my experience...

ebay pcm ( immobilizer chip removed , yes , opened it and saw a small pcb removed ) , battery / fuses disconnected and installed . no problems starting car even thought ebay pcm from a Rover 416

No bridging service connector........ MIL light OFF than ON.....start car and driving MIL light stayed ON. turn off car KEY light flash 5 times.

Bridging service connector....MIL flash once than OFF , SRS OFF than back ON...no recorded DTC...start car and driving , MIL stayed OFF , SRS stayed ON...turn off car KEY light flash 5 times.

From above i would think car detected Immobilizer issue.... install back my not faulty pcm.... don't wanted immobilizer issue render honda unstartable.

Back to the tedious fill up , record mileage , fill up , record mileage........ work out average mpg.

Any suggestions on particular item i should look into for better MPG ,like the air filter , is most welcome and appreciated .

many thanks