1999 Ford F-150 error code P0161 and P1000

NORSEMAN3971

MEMBER
1999 FORD F-150
V8
4WD
AUTOMATIC
103,000 MILES

I have been trying to diagnose a check engine light. It would start really hard when cold (0 F and colder) Changed air bypass valve. Also changed fuel filter. Now truck runs great but still have error codes, but is sucking gas down like it thinks it is a 460cid.

Read codes. Changed both downstream O2 sensors. No change in codes. Borrowed a friends computer scanner/tester. I can see O2 sensor on bank 2 sensor 2 has 8 milliamps once warmed up. At first it was 4. But I pulled PCM to get part # and put it back in and now it is 8. I put a second new 02 sensor in bank 2 sensor 2 and still no change. Looked over wires, can't find chaffing. I don't do off road and do mostly highway or intown driving and truck hasn't been abused.
With P1000 code it is telling me the OBC isn't going all the way through not sure if that is a default once an error is reached in the initial checking and stops further stuff in a default mode.
Having eliminated the actual O2 sensors and did a fair job checking the wires, is it safe to say the PCM is bad and I need to get a new one? Or should I tear into the wiring harnesses looking for a short or break?
I have a new (read used from junk yard) pcm sitting there to go to dealer to get programed. Just looking for other avenues to troubleshoot before the dealership rapes me with their obsurd hourly charges.
Thanks.

3 Replies

DAVE H

MECHANIC
13,384 POSTS

Hello. Thanks for the donation. Much appreciated

Try disconnecting the battery for 5 minutes (making sure you have the radio code handy if equipped) reinstall battery terminals then complete this drive cycle test ! Let me know

OBD-II Drive Cycle
NOTE:The IAT PID must be between 50-100 °F (10-38 °C) during the OBD-II drive cycle to enter into all the OBD-II monitors. The FLI PID must be between 15% and 85% at all times.

Drive in stop-and-go traffic with at least 4 idle periods (30 seconds each) while observing the status of the OBD-II monitor on the scan tool. If the Exhaust Gas Recirculation (EGR), Heated Oxygen Sensor (HO2S), Evaporative (EVAP) emission, secondary Air (AIR) (if applicable) or catalyst efficiency monitor have not completed, drive on the highway at a constant speed over 40 mph not to exceed 65 mph for up to 15 minutes. Heavy accelerations, sudden decelerations and wide open throttles are not recommended. If the scan tool sends out a three pulse beep at any time, the OBD-II drive cycle has completed.
NOTE:Vehicles equipped with the EVAP purge flow system or EVAP vapor management flow system monitor do not require EVAP monitor completion to clear the DTC P1000.

If the EGR, HO2S, EVAP, secondary AIR (if applicable) or catalyst efficiency monitor has not completed, perform the corresponding monitor verification drive cycle. See MONITOR REPAIR VERIFICATION DRIVE CYCLES.
Bring the vehicle to a stop and retrieve Continuous Memory DTCs to verify the DTC P1000 has been erased.

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Monday, February 16th, 2009 AT 9:37 AM

NORSEMAN3971

MEMBER
2 POSTS

I took off the negative cable for 10 minutes. Reattached. Let truck warm for 15 minutes. Drove 7+ miles at 40mph with a few stops trying to get 30 seconds. Jumped on interestate. Drove at 62-63mph for 7 miles. Got off turned around and drove 10 miles the other way doing the same speed.

I am guessing IAT PID is intake air temp. I'm in Wisconsin and it is 29 F out right now. I won't get 50-100 F for at least 6 more weeks.

What is FLI PID?

I have the same DTC 1000 and 0161. I am more concerned about the o2 sensor bank 2 sensor 2 which sits on drivers side down from cat. At normal engine temps the other sensors have 710-850 for milliamps while b2s2 is at 8 milliamps. And for actuall sensing the b2s2 ranges from.01 to.06 while the others are at.17 to.85. Again, I replaced this sensor twice and have the same numbers.

I have at my disposal the Genisys scanning computer so I can read out almost all data and codes in the system.

Any other thoughts as for what to troubleshoot. What to read out with a meter?
Should I be more concerned with the DTC P1000 code? Or should I just go replace the PCM that I got and let the dealership finish. Although I prefer to keep the dealership's fingers out of my truck.

Thanks for all assistance. It is appreciated.
I'll donate more if my truck gets fixed with your assistance.

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Monday, February 16th, 2009 AT 11:52 AM

DAVE H

MECHANIC
13,384 POSTS

FLI PID is fuel level input paremeter identification .. P1000 is telling you the PCM is not able to complete self test .. which it won't because of the PO161 fault code .. try these tests ?

30) DTC P0135, P0141, P0155 Or P0161

DTCs received separately indicate a short to ground or open circuit in HO2S heater circuit. DTCs received in pairs, such as P0135 and P0155 or P0141 and P0161, indicate HO2S heater circuit is shorted to a power source of more than 2 volts. HO2S DTC identification is as follows:
DTC P0135 is for HO2S-11.
DTC P0141 is for HO2S-12.
DTC P0155 is for HO2S-22.
DTC P0161 is for HO2S-22.
Refer to illustrations for HO2S identification.

Possible causes are:
Signal shorted in wiring harness or HO2S.
Water in connectors.
Cut or pulled wires.
Open in GND or VPWR circuit.
Corroded terminals.
Faulty HO2S heater.
Inspect HO2S connectors for loose, damaged or corroded terminals. Repair as necessary. If HO2S connectors are okay, go to next step.
31) Perform KOEO Self-Test

Start engine and operate at 2000 RPM for one minute. Turn ignition off. Perform KOEO ON-DEMAND SELF-TEST. If DTC P0135, P0141, P0155 or P0161 is present, go to next step. If specified DTCs are not present, fault is intermittent. Go to TEST Z.
32) Check For Voltage At HO2S Heater Wiring Harness Connector

Turn ignition off. Disconnect suspect HO2S. Inspect wiring harness for damage and repair as necessary. Turn ignition on. Measure voltage between SIG RTN and VPWR terminals at suspect HO2S wiring harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, check circuit fuse. Replace as necessary. If fuse is okay, repair open circuit.
33) Check HO2S Heater Resistance

Turn ignition off. With suspect sensor disconnected, measure resistance between HO2S HTR terminal and VPWR terminal at suspect HO2S. If resistance is 3-30 ohms, go to next step. If resistance is not 3-30 ohms, replace HO2S.
34) Check HO2S Case For Short Circuit

Measure resistance between HO2S HTR terminal at HO2S and HO2S case. Measure resistance between HO2S HTR terminal and SIG RTN terminal at HO2S. Also measure resistance between VPWR terminal at HO2S and HO2S case. If all resistance readings are more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, replace HO2S.
35) Check For Short Circuit

Disconnect scan tool from DLC. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between HO2S HTR terminal and SIG RTN and VPWR terminals at suspect HO2S wiring harness connector. See Fig. 103 or Fig. 104 . If both resistance readings are more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, repair short circuit.
36) Check For Open Circuit

Leave ignition off and HO2S disconnected. Measure resistance between HO2S HTR terminal at suspect HO2S wiring harness connector and appropriate HO2S HTR pin at PCM connector. See HO2S PCM PIN IDENTIFICATION (CONTOUR, COUGAR & MYSTIQUE) table. See Fig. 103If resistance is 4 ohms or more, repair open circuit or excessive resistance in wiring harness. If resistance is less than 4 ohms, replace PCM.