If it's a CA car (w/ the Diag Module), the codes are

DTC - - - - Cause of failure
2: - - - - Oxygen sensor faulty (G3/2)
26: - - - - Upshift delay switchover valve (Y3/3), open or short

Check my page (www house below) and select menu #1 for more info on the valve (Y3/3) and O2 sensor (G3/2). Check menu# 6 for Diag Module.

It's probably a bad/broken vacuum line for Y3/3. O2 sensor could be bad

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Regards . . . . JimF
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'94 S500 Cpe

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