Re: Is this even close to right? ('88 5.0)
Reply #54 –
(DH3) Service code 53: Attempt to generate service code 63
- Key off, wait 10 seconds.
- Disconnect TP sensor harness at throttle body.
- Rerun KOEO self-test.
- Is code 63 present? (Ignore all other codes at this time)
-- Yes - go to DH4
-- No - go to DH5
(DH4) Check voltage Vref to Signal Return
- Key off, wait 10 seconds.
- Disconnect TP sensor harness at throttle body.
- DVOM on 20-volt scale.
- Key on, engine off.
- Measure voltage between VREF and SIGNAL RETURN at the connector (should be orange/white and black/white).
- Is voltage between 4.0 and 6.0 volt?
-- Yes - Replace TP sensor. Rerun quick test.
-- No - Go to pinpoint test C1
(DH5) Check TP signal for short to ground
- Key off, wait 10 seconds.
- Disconnect TP sensor harness at throttle body.
- DVOM on 20,000 ohm scale.
- Disconnect processor.
- Install breakout box, leave processor disconnected.
- Measure resistance between pin 47 and pins 26 and 57 at the breakout box.
- Are both resistances greater than 10,000 ohms?
-- Yes - Remove breakout box. Replace processor. ($$$) Reconnect TP sensor. Rerun Quick Test.
-- No - Service short circuit. Remove breakout box. Reconnect TP sensor and processor. Rerun Quick Test.