Stop / Start Fault P1656

[MrSweetE90]

Hi All,

Another day, another problem it seems I replaced a faulty glow plug a few weeks back and finally got stop start working again, it came up with a fault again when it started the car up again so expected another glow plug. When I got home I checked the resistance of each glow plug and all are fine, however I do get the error code P1656. I'm having a Google but it's a bit tricky as that P code seems to different for different cars such as Toyota for example. So does anybody know what this means for the J10 1.6 dci R9M Engine?

[MrSweetE90]

Cleared fault, no error message anymore but after a quick drive stop start won't kick in leading me to believe the battery is on its way out.

[calnorth]

From R9M diagnostics:

P1656 ENGINE RESTART BYPASS RELAY

At a glance I think this relay and ECU prevent a Restart attempt when Batt volts at 8v or less. Possible causes:

• Harness and connectors
(Engine restart bypass relay circuit is open or shorted.)
(Engine restart bypass control relay circuit is open or shorted.)
• Engine restart bypass relay
• Engine restart bypass control relay

No mention of a bad battery

No idea where this relay or circuitry is.

[MrSweetE90]

Hi Calnorth,

Despite clearing the codes my dashboard lit up like a Christmas tree and showed all the ABS, Traction control, power steering and dashboard lights fading and indicators sometimes coming on sometimes not. This is exactly the same thing that happened when it went into Nissan. However, Nissan diagnosed the exhaust pressure sensor which I said I suspected but then I couldn't join the dots to why the indicators and dashboard would fade out. Anyhow, it happened again but this time the actual AA came out rather than their partner company and the AA battery tester after some time came up "replace battery"

I followed him to eurocarparts, he paid £210 for a Bosch battery and I just paid £35 excess on my parts and garage cover. Absolutely love having parts and garage cover, I must have claimed on that like 6 times now between the Nissan and the BMW lol.