Confounded by multiple CELs - need help
 

Hey guys,

1998 with 108k on the clock and I need to solve my CEL before I can pass emissions here in Illinois.

I pulled my ODBII codes couple weeks ago: p0131, p0151, p0138, p0158, p1115, p1119, p1117, and p1121. Hmmm... strange, not all my O2 sensors would fail at once, right? Regardless, I purchased 4 universal 02 sensors and spliced and installed correctly.

This did NOT solve the CELs. I went further upstream to solve, I started with cleaning the MAF and then replacing the MAF with a new unit.

Now I've got the probable culprits replaced for these codes, yet no solution.

The only symptom I can report is a slightly rough idle and a noticeable hesitation at around 5k RPM with WOT (wide open throttle).

Would the wrong battery possible trigger these CELs? I don't want to even think about a costly DME replacement.... I'm outta ideas and could use some help gentlemen.

Thanks
Matt

I just love it when people start swapping out expensive parts without doing the appropriate diagnostics first. But thanks for helping to move the economy forward.

That said:

P0131 Cylinder 1-3 O2 sensor ahead of cat shorted or wrong voltage
P0138 Same bank, same problem, sensor behind the cat
P0151 and 0158, similar codes, other bank
P1115 and 1119, heating current too low on both sensors ahead of cats
P1117 and 1121, more low heating circuit current levels

All of the diagnostics trees for these codes have only two common possible source items listed:

1. Wiring harness problem.
2. DME

I assume you've reset the codes and they keep coming back. If it is the DME, check these guys out for repair: Specialized ECU Repair, Replacement, & Testing - Restore or Exchange your Electronic Control Unit (ECU)

Any wiring issues?

May also be a oxygen sensor relay if it is low/no voltage supply problem. Wiring diagram shows relay position #2 in relay holder #2 (Relay holder 2 is located on the left-hand side of the rear luggage compartment. It can be unclipped and pulled out.)