Code 18 I.D.M. (spout circuit grounded)
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Code 18 I.D.M. (spout circuit grounded)
Hey ford people I'm getting the 18 code on my obs 91 f150. Also having idle problems. I believe that is due to my egr not closing properly (code 33) any suggestions?
Fleet Owner
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From: Kentucky
Code 18 has different definitions depending on when it was displayed. Was this displayed during the stored code (aka Continuous Memory) display or during the Key On Engine Running (KOER) tests?
Code 18 (CM): Loss of IDM input to processor/SPOUT circuit grounded
Code 18 (KOER): SPOUT circuit open
I would ask the same about Code 33...
Code 18 (CM): Loss of IDM input to processor/SPOUT circuit grounded
Code 18 (KOER): SPOUT circuit open
I would ask the same about Code 33...
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Code 33: EGR valve opening not detected.
Verify there is manifold going to the EGR Valve Regulator (EVR) and the line leading from the EVR to the EGR valve is intact.
Code 18 (CM): IDM circuit failure or SPOUT circuit grounded.
Verify the IDM signal is getting to Pin 4 of the computer (PCM).
The IDM signal is derived by the Ignition Suppression Resistor depicted in this diagram:
Since the code has more than one definition as a CM code, I would suggest you remove the SPOUT plug, use a DVM set to measure ohms, place the black lead to a known good ground, then use the red lead to verify there is no short to ground on either side of the SPOUT plug. I would expect a very high resistance measurement at the very least.
Verify there is manifold going to the EGR Valve Regulator (EVR) and the line leading from the EVR to the EGR valve is intact.
Code 18 (CM): IDM circuit failure or SPOUT circuit grounded.
Verify the IDM signal is getting to Pin 4 of the computer (PCM).
The IDM signal is derived by the Ignition Suppression Resistor depicted in this diagram:
Since the code has more than one definition as a CM code, I would suggest you remove the SPOUT plug, use a DVM set to measure ohms, place the black lead to a known good ground, then use the red lead to verify there is no short to ground on either side of the SPOUT plug. I would expect a very high resistance measurement at the very least.
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Goulette55
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Jan 20, 2006 09:19 PM
