Check engine light

Hi,

Thank you for the reply. With key on, engine off and NO check engine light illuminated. The ECM will not flash anything. The light must be on first. Yes, I tried to retrieve something by jumping the diagnostic connector by the battery. Nothing happens. Thank you for the help.

I find it curious that the O/D light flashes, but only when the check engine light is not on.
There is no pattern to the O/D light flashes, just steady, flash, flash, flash.

The manual I have "sic" only says to diagnose the check engine light circuit if the light is not on.

I will try the fuse option and see what happens.
Thanks again.
Stay tuned, Curt

Monday May 9.
Hi, thank you for the diagrams and pics. What a huge help.
I searched the internet for the flow chart, but with no luck.
Then I stumbled upon 2CarPros.
Bless you all.
I'm a full-time caregiver to my mom so time with car is limited and the weather here in Tri-cities WA, has been rainy.
Looks like this Wednesday is car day for me.
I'll post what I find later in the day.
Thanks a bunch. Curt.

Morning, sorry I did not get to the Suzuki.
Weather here windy-cloudy-rainy.
I'm working in the driveway, so it looks like Sat-or-Sun.
Thanks, Curt

Monday 16
Hi, I got the main relay checks done as per the diagram pictures you sent.
Battery voltage is present where it should be. At the relay and wiring harness plug both shows B+ voltage.
The relay clicks and I can feel it as well in my hand when turning the key to run position.
I fallowed the flow (yes-no) chart twice and got the same results.
Poor connections at A12 and A13-OR-ECM and it's circuit.
I inspected the plug ends and carefully, bent-let's-say, the connections for A12 and A13 to ensure a tight connection.
No corrosion visible in any way.
Upon repeating the flow chart test, I got the same results.
."Check ECM circuit".
I'm going to check all grounds and battery positive voltage where I can find them.
Like.
B+ at ignitor
ECM pin #A1 for B+
ECM grounds at B1--B2--and--B14
grounds under hood for B+ and any voltage drops.
When I get some real numbers I'll respond. Thanks for the help.
I'm still thrown by the O/D light flashing though.
Curt

May 17,
Hi. I got some real numbers.
Static battery voltage=12.55 VDC.

6-grounds in engine bay=12.54-to-12.55 VB+.

Full battery voltage at both sides of all fuses (under dash) with key on.

Battery voltage at main relay=12.55 at terminals A-B-C.
Voltage at D=0.80 VDC (back probe blue wire A10 with key on, relay connected to harness plug).

Battery voltage at ECM pins.
A1=12.55 VDC
A22=10.70 (cranking VDC).

I looked closely at ECM wires A10-A12-A13, all appear tight and clean.
This ECM is a replacement some three years ago for the OEM unit.
During that time the car always started, ran and drove without issues.

At this point I'm condemning the ECM. Looks like it is not completing the ground circuit inside the ECM itself. (Is this conclusion correct? As the main relay is working.)
What say you?
Did I miss something?
Curt

I found this on the internet.

I have this picture as well. Note that cavity pin A10 claims B+ voltage should be 0.50VDC or less. I got 0.80VDC. The main relay "clicks" when turning the key to run. So, is ECM working properly then? If so, then why no CEL light and, OD/Off light blinks.
I looked for TCM diagnostic plug so I could "jump" it and retrieve any codes. No plug exists.
I'm stumped.
Curt

I cannot find a diagnostic flow chart for just the CEL circuit. The Chilton manual I have for Suzuki's just says "If no CEL is lit with key on then diagnose the circuit. But no details. It is not a burned-out bulb as I can make it come on by using the Noid light reset switch.
Any ideas would help. Thanks, Curt.

Well, I'm understanding that it means voltage output from ECM at blue wire to main relay should be 0.50 VDC. I do not know what it should be.
You're saying it should be FULL battery voltage?
There have been zero issues with the automatic transmission since 2013 when I got the car.
The OEM ECM acted up badly some three years ago, then the transmission was wonky but only because of the bad ECM. Once I replaced the ECM the transmission operated without issue.
Thank you for the help.
Curt.

The last picture I posted is of the wiring harness at the ECM. The person who posted it claims that those are the voltages one should be seeing at the harness when probing it.